Sins of the Father (episode)
Worf is plunged head-first into the politics of the Klingon Empire when his deceased father is accused of treason.

Summary

Teaser
"Captain's log, Stardate 43685.2. As part of an exchange program, we're taking aboard a Klingon officer to return the recent visit of Commander Riker to the cruiser Pagh."

The Klingon Commander Kurn is temporarily assigned to the  as acting first officer as part of the Federation-Klingon Officer Exchange Program. Earlier, in 2365, Commander and Enterprise first officer William Riker served in a similar capacity aboard the . Kurn, in his new role, immediately tries to impose "Klingon-style" discipline aboard the Starfleet vessel, with Captain Jean-Luc Picard's full approval. Kurn disciplines Wesley Crusher in front of the bridge crew while the acting ensign whispers with Data while Kurn is speaking to the crew. Kurn has Ensign Crusher set course for the outer cometary cloud of the system, with Kurn angrily ordering him to increase speed to one-third impulse power. The surprised crew find Kurn's method excessively harsh and draconian.

Act One

When La Forge and Wesley complain privately to Riker in Ten Forward about Kurn's aggressive command style, he reminds them that Kurn simply has a different style of command, and that Klingons believe in obedience and strict adherence to regulations. However, it is notable that the only person Kurn has not been giving a hard time is "the one person who wouldn't really mind it": Worf.

Kurn gives Worf the assignment of scanning the 2,000 asteroids in a field at a range of 300,000 kilometers: none in their flight path. He praises him sarcastically for his efficiency during an easy navigational procedure on the bridge. Worf is angered at being patronized, but resists confronting a superior officer.

While in a turbolift on his way to the captain's dining room, Riker tells Kurn it took him some getting used to Klingon culture while serving on the Pagh. Riker notes that the crew of the Enterprise must take some getting used to for him and he offers to assist Kurn with suggestions in working with the crew. Kurn respectfully declines the offer. Riker forcefully reminds Kurn that this is not a Klingon vessel. Kurn concurs and reminds Riker that on a Klingon ship, he would be killed for offering up such a "suggestion".

A special dinner is prepared at the captain's mess in honor of Kurn, who understands the honor and is prepared to sample some of the food, even though some of it is cooked—but he doesn't like it, and bluntly explains that it is too bland a taste. La Forge observes that it seems to agree with Worf, earning Worf a contemptuous look from Kurn.

After dinner, filled with rage, Worf goes to Kurn's quarters to demand an explanation. When the other expresses doubt of Worf's Klingon instincts, Worf erupts in a violent outburst. Kurn is pleased and says he's been testing Worf to see just how Klingon he was, revealing that he is really Worf's younger brother.

Act Two

Kurn explains that he was barely a year old when their family went to Khitomer, and they weren't going to stay there for long, so he had been left to stay with their father's friend, Lorgh until their return, and so escaped the massacre. Worf explains to Kurn that the Starfleet officer that rescued him was told by the Klingon High Command that he had no living relatives, believing that Kurn was with the family and therefore killed at Khitomer. After the massacre, Lorgh adopted Kurn as his son and kept him in his family. When Kurn reached the Age of Ascension, he was told the truth about his bloodline.

Kurn has sought Worf out because their father, Mogh, is accused of treason by the Klingon High Council. Supposedly, he had given the Romulans defense access codes allowing them to lower the shields of the Khitomer outpost just before the Romulan attack. Kurn had lived all these years, hiding his identity by masquerading as the son of Lorgh, but when he learned of the Council's action, he came to Worf, asking him to challenge the judgment as Mogh's elder son.

Worf goes to Picard and explains this to him, asking for leave so he can face the High Council. Picard says that since Worf is accused of a capital crime, it would be better if he were standing at Worf's side as he made his challenge. Picard commands Kurn to set course for the First City of the Klingon homeworld. Kurn is surprised; he hadn't expected the Enterprise itself to change course. Now he respects Worf more deeply than ever.

On the way home, Kurn asks Worf in Ten Forward if he can be his Cha'DIch, or ritual second; while Worf is accused, he will not be allowed in any duels or fights. Worf agrees, and Kurn speaks the traditional words of acceptance: "I accept with honor. May your enemies tremble before you." Then Worf tells Kurn that he must not reveal his true bloodline. Kurn protests, and Worf reminds him that, on the Enterprise, Kurn is the superior officer, but on the Klingon homeworld, Worf is the elder brother, and Kurn must obey him.

Once they arrive at Qo'noS, Worf and Kurn beam down with Picard and Riker accompanying them. Worf pronounces his challenge before the Council and faces the accusations of Duras, the son of Mogh's greatest rival. Worf acknowledges that he is prepared to face the consequences with his very life if his challenge fails. "I am Worf, son of Mogh. I have come to challenge the lies that have been spoken of my father!", he defiantly states to the High Council.

Act Three

Duras accuses Worf of forsaking his heritage for the Federation, but Picard tells the council that Worf has served under his command with distinction, and as such, has earned him Picard's admiration and respect. Appealing to the council's better natures, Picard says he trusts their wisdom will guide them to clear Worf's family name and return him to duty. Chancellor K'mpec notes the trust of a commanding officer is admirable and notes it for the record.

Duras testifies that a transmission of access codes went out from the outpost to the Romulan patrol ships which allowed them to dismantle the outposts' shields. Thousands of Klingons died on Khitomer, including Duras' father. Duras calls Mogh a traitor and because Worf has brought this challenge, Duras calls him a traitor as well, backhanding Worf in the traditions of their people. Duras then rips Worf's baldric off of him, telling Worf he is unworthy to wear the emblems of their people. Worf replies, "it is a good day to die, Duras, and the day is not yet over." 

During a recess of the council, K'mpec meets with Worf and tries to persuade him into abandoning his challenge. Shocked at this, Worf asks K'mpec why he would have him lay aside his father's honor, but K'mpec will not allow himself to be questioned and advises Worf to leave before he is condemned as a traitor.

Kurn has received a note to meet someone in an isolated corridor; it is Duras. Duras reveals that he knows Kurn's true bloodline and tries to blackmail him into turning against Worf. Disgusted, Kurn refuses, and Duras' assassins attack him with a kut'luch, the ceremonial weapon of an assassin, which inflicts serious wounds.

Act Four

Although Beverly Crusher reassures Worf that due to Kurn's phenomenal metabolic recovery, his wounds are not life-threatening. Worf tells her she should have let him die because he'll be executed anyway – now that someone knows he is Worf's brother, Kurn will share Worf's fate if the challenge is unsuccessful. Later, Worf voices his worries that the very High Council itself is against him to Picard, who attempts to reassure him. Worf requests that he be allowed to select another Cha’DIch, from among the crew this time, which Picard assents to. Promptly, Worf asks the captain to be his Cha'DIch, giving him the option to refuse with no dishonor. Picard is touched, but demurs by pointing out that there are many stronger and younger people that he can choose. In response, Worf confidently states that there is no one better qualified. Picard pleases Worf by reciting the same traditional acceptance, in Klingon.

Surprised by Worf's new Cha'DIch, Duras questions Picard's validity as Cha'DIch, but Picard tells Duras that he's not here to command, to which Duras smirks and responds that he has to fight as well, which he believes isn't something that is taught by Starfleet. Coldly, Picard informs Duras that he is welcome to test that assumption at his leisure, wiping the grin off of Duras’ face.

The Enterprise crew investigate the Khitomer Massacre on their own. The  was the first ship on the scene of the disaster; Data contacts Starfleet for copies of the Intrepids logs. Meanwhile, La Forge and Data have gotten into the Klingon Central information net and discovered that the Klingons recently captured a Romulan ship with information about Khitomer in the ship's logs and that's how they found out about the treachery.

Upon comparing the information in the Klingon archives with the Intrepids logs, La Forge and Data discover that there is a discrepancy in the transmissions. The evidence which supported Mogh's guilt was faked. They also discover another survivor of the Khitomer Massacre, a woman named Kahlest, is found to be still alive and residing in the Old Quarter of the First City. Riker informs Picard about this during the second Council session and asks Worf, who says that Kahlest was his nurse and that he thought she had died. Picard tells Worf he must find her and bring her before the Council. Worf recommends that he not go alone, as it is too dangerous. Picard tells him, "Hey, I'm your Cha'DIch."

Act Five

Picard journeys into the Old Quarter and finds Kahlest's home. Kahlest informs him that she considers her life to have ended after Khitomer and that she is waiting to die. Picard tries to persuade Kahlest to accompany him back to the High Council chamber, appealing to her sense of honor by telling her that the family that she once served proudly needs her again. She refuses, and a disconcerted Picard leaves. Just outside Kahlest's door, he is ambushed by Duras' assassins. He manages to overcome one and Kahlest, emerging from her home, throws a knife and kills the other. Impressed with Picard’s bravery, Kahlest now agrees to accompany him back to the High Council for the purpose of testifying for Worf. She also reveals that K'mpec was once romantically interested in her, but she wasn't attracted to him; he was too fat.

Just as K'mpec is about to pronounce judgment on Worf, Picard enters with Kahlest. K’mpec’s eyes flash with recognition as he sees Kahlest and he calls a recess. In a private session, Picard demands that she be allowed to testify in open council in accordance with Klingon law. Duras threatens to kill Kahlest right then and there so as to silence her. K'mpec, incensed, silences him by asking him if he would really kill an old woman to cover his dishonor. Picard instantly sees that the whole Council proceeding is a farce: a frame-up to save Duras, not Worf, from disgrace. K'mpec tells Kahlest she is free to go, adding, "It is good to see you again", to which she contemptuously responds, "You are still fat, K'mpec."

Worf angrily demands an explanation for the Council judging Mogh guilty, despite the fact they knew he was innocent. K'mpec privately explains the truth: When Klingons captured the Romulan ship with the records, they learned of the treachery behind the Khitomer Massacre; this soon became common knowledge, and someone had to answer for that treachery. Fortunately, only the Council knew who transmitted his code: not Mogh, but Ja'rod, Duras' father. 

Beside himself, Worf violently points out that Duras should have been made to pay for the sins of Ja’rod, but K'mpec reveals that the Duras family is too powerful and to expose him would likely split the Empire apart and plunge it into a civil war. In order to avoid that, they decided to use Mogh as a scapegoat, believing that Worf, since he was in Starfleet, would not challenge the judgment. None of them realized that Kurn was Mogh's second child. But now things have progressed too far, and both sons of Mogh must die.

Offended and outraged by the sheer hypocrisy of K'mpec and the Council, Picard demands to know what this says for an Empire which professes to value honor above all else. K'mpec adamantly says one family's honor must be sacrificed to preserve that Empire, not the other way around. Picard – now speaking in his official capacity as captain of the USS Enterprise and a representative of the Federation – insists that Worf's challenge has succeeded, and he refuses to hand Worf or Kurn over for execution. When K'mpec threatens to end the alliance, Picard retorts that their alliance is not based on lies. If they must protect their secrets, then so be it but Picard will not allow the needless sacrifice of these two men.

Worf then volunteers to die for the sake of the Klingon Empire. Picard begins to object but Worf tells his Cha'DIch to be silent. Worf asks for Kurn's life to be spared. Duras rejects this, as Kurn's honor would then demand revenge. Worf then offers to accept discommendation if Kurn is allowed to live. K'mpec instantly sees this as a neat solution to their dilemma but doing so would be the same as admitting his father's guilt. Worf simply says "So be it."  K'mpec affirms his belief that Worf's heart is truly Klingon and proclaims that this matter will never be spoken of again. Duras, satisfied that matters have been arranged to his and his family's benefit, starts to exit the chamber, but Worf stops him and does what tradition demands: saying to his face, "You are the son of a traitor" and viciously backhanding him. K'mpec nods in approval at this.

In a room behind the council chambers, Kurn tells Picard that he was ready to die for his brother and his family's honor. Picard attempts to console Kurn with the reasons behind Worf’s sacrifice; Worf is looking ahead, knowing Kurn must live in order to restore that honor: "There will be another day, Commander. Do not forget what he does here today. Do not let your children forget." Picard and Kurn join Worf in the middle of the council chambers and the council members gather in a circle around Worf. Worf says the ritual words, "tlhIH ghIj jIHyoj" ("I fear your judgment"); K'mpec replies, "biHnuch!" ("Coward!"), and one by one, the Council members cross their arms and turn their backs (turning to their right) on him in ritual ostracism, all except Kurn, who stares at Worf pleadingly. Worf softly tells Kurn that he must do it also. Kurn very reluctantly complies, but instead of turning to his right, he turns to his left. The whole assembly having turned their backs, Worf and Picard leave the Council Chamber and return to the Enterprise.

Log entries
 Captain's log, USS Enterprise (NCC-1701-D), 2366

Memorable quotes
"One does not patronize a Klingon warrior."
 - Riker

"Do you wish to SPEAK, Acting Ensign Wesley Crusher?"
 - Kurn

"I imagine it must be very difficult for you to work with a crew that is so different. I would be happy to guide you in that regard, if it would be helpful." 
"No, Commander, it wouldn't." 
"This is not a Klingon ship, sir." 
"No, Commander, it is not. If it were a Klingon ship, I would've killed you for offering your suggestion." 
 - Riker and Kurn

"How long has this bird been dead? It appears to have been lying in the sun for quite some time." 
"Well, it's not dead, it's been replicated. And you do understand that we cook most of our foods…" 
"Ah yes, I was told to prepare for that. I shall try some of your burned replicated bird meat."
 - Kurn and La Forge

"I never kill anyone at the supper table, Mr. La Forge."
 - Kurn

"I am Klingon! If you doubt it, a demonstration can be arranged."
"That is a response of a Klingon. The response I would expect from my older brother."
 - Worf and Kurn

"Will you grant my leave, Captain?" 
"No – if I understand correctly, a Starfleet officer, a respected member of my crew, could be charged with a capital crime. Your actions on this matter will reflect on this ship, and on the Federation – therefore, it seems only appropriate that your captain should be at your side while you make your challenge… I'm sure you would do no less for me."
 - Worf and Picard

"I am Worf, son of Mogh. I have come to challenge the lies that have been spoken of my father!"
 - Worf, to the Klingon High Council

"I should've known. Worf was right. It is a good day to die."
"The time has not yet come. It does not have to come for many turns. I know who you are, Kurn, son of Mogh."
"What?!"
"It was a wise choice to hide your family name. Do not err now by embracing it again, for you only embrace death."
"We shall see."
"Worf has made a choice and he will die for it. But you can still be safe. Let him stand alone."
"He is my brother! I will not betray him!!"
"Then you will die for him!!"
 - Kurn and Duras

"Are you adjusting to your new environment, Commander?"
"I find the constraints a bit difficult to conform to. Just a short while ago, I had to stop myself from killing Commander Riker."
 - Troi and Kurn

"For many turns, the truth about Khitomer has lain dormant. Unknown. Now the truth has been revealed. The traitor, Mogh, sent the defense access codes to the Romulan patrol ships, allowing them to destroy the outpost. Thousands died on Khitomer! My father died on Khitomer! Their deaths must be avenged. Your father was a traitor. By posing this challenge, you are a traitor! You will not wear the emblems of our people. You are a fool, and your challenge can only result in a fool's death."
"It is a good day to die, Duras, and the day is not yet over."
 - Duras and Worf

"This is not your world, Human. You do not command here."
"I'm not here to command."
"Then you must be ready to fight. Something Starfleet does not teach you."
"You may test that assumption at your convenience."
 - Duras and Picard

"My appreciation, madam."
 - Picard, to Kahlest after she kills a Klingon who was about to murder him

"THIS Ha'DIbaH SHOULD’VE BEEN FED TO THE DOGS!!"
 - Worf, pointing at Duras after learning the truth

"You are brave, cha'DIch. Worf chose well."
 - Kahlest, after Picard fights off Duras' assassins

"K'mpec would remember Kahlest. I caught his eye back then. But he was too fat."
 - Kahlest

"It is good to see you again."
"You are still fat, K'mpec."
 - K'mpec and Kahlest

"You admit the truth, and yet you expect him to accept punishment? What does this say of an empire who holds honor so dear?"
"The empire will not be destroyed for one family's honor."
"Unacceptable, K'mpec!"
"You have no say in this, cha'DIch!"
"I speak now as the captain of the USS Enterprise and Lieutenant Worf's commanding officer! You will not execute a member of my crew, nor will I turn his brother over to you!"
"This is not the Federation, Picard. If you defy an order of the High Council, the alliance with the Federation could fall to dust."
"The alliance with the Federation is not based on lies, K'mpec. Protect your secrets if you must, but you will not sacrifice these men."
 - Picard, K'mpec, and Duras

"The cha'DIch will be silent!"
 - Worf, to Captain Picard

"You are the son of a traitor."
 - Worf, to Duras

Background information

Production history 
 Final draft script:  
 Premiere airdate: 
 First UK airdate:

Story and production 
 This story began life as two different scripts, one by Drew Deighan which featured Worf's father being accused of treason, and another script by Beth Woods, in which Worf's brother came aboard the Enterprise. Shortly after officially joining the writing staff, Ronald D. Moore was given the two scripts by Michael Piller and asked to combine them into a single story. Due to Moore's comparative inexperience in writing for television, the more experienced W. Reed Moran was asked by Piller to work with Moore, only for Moran to be removed from the writing process after completion of the first draft due to his own lack of familiarity with the series, with Moore and Piller subsequently seeing the script through to completion. (TNG Season 3 Blu-ray, episode commentary)
 Moore recalled, "I was in love with 'Sins of the Father' and I fought for it when there was some question about which way we were going to go with it. I really like the fact Worf took it on the chin that episode. It said he was willing to stand up and do the right thing for his people, even if they weren't going to do the right thing by him. Patrick and I were at the Saturn Awards together, and he made a really good suggestion. When Worf is asking Picard to be his Cha'DIch, Picard originally says a single Klingon word, but Patrick thought it would be nice if Picard knew the whole line of ritual. At that time there wasn't a formal ritual, and there wasn't one for Kurn either, so I went back and wrote a line for him to say in Klingon and I tied it into Picard." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 193)
 Director Les Landau recalled, "Here was an opportunity to explore the Klingon world in depth from beginning to end. Meaning that Ron Moore came up with a wonderful story which Richard James, the art director, and Jim Mees, the set decorator, had to visualize in terms of set design and set decoration. Additionally, to which Marvin Rush, the cameraman, had to conceptually find a visual representation of what the Klingon world was all about. I think all three of those gentlemen accomplished that task totally. In fact, Richard and Jim went on to win Emmy Awards for that episode, which I'm very proud of. Marvin's work speaks for itself. It was visually one of the most dynamic episodes ever done. It looks like a feature film. There were long detailed conversations about how, conceptually, we should deal with them. Ultimately, Rick Berman gave the final approval for each and every one of the ideas and details, and we showed a world that was heretofore never seen before, and which the audience craves to see more of. I was never one of the original Star Trek fans, however. My attitude was, is and always will be to never see what has come before, but to go where none have before and visualize what is in my thinking and mind as to what the visuals should be, which is dictated by the storyline. We must always come back to the words and what the story is, because without it, we have nothing to tell. After all, film and episodic television is nothing if not telling a story." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 194)
 As an in-joke, the captain of the  is named Drew Dieghan on a monitor screen, after the writer who submitted the spec script upon which this episode was based. ()
 The design of the Klingon Great Hall (and other sets in the episode) won an Emmy Award for Best Art Direction for Star Trek: The Next Generation production designer Richard James. The exterior of the Great Hall and the surrounding First City was a matte painting created by Syd Dutton at Illusion Arts. ()
 The Great Hall in this episode was built off the quite large Tanuga IV research station set that was built for , earlier in the third season.
 Among the items which were sold off on the It's A Wrap! sale and auction on eBay was a Klingon assassin's knife, seen in this episode.

Continuity 
 This episode marks the first depiction of the Klingon homeworld Qo'noS.
 The episode refers to William Riker's service on the  and other events from . It also sets up several future themes, such as the House of Duras and the underpinnings to the Klingon Civil War.
 Tony Todd makes his first appearance as Kurn in this episode. He reprises the role in ,  and the  episode .
 The over-the-shoulder cloak with the medals that K'mpec wore as High Council leader was the same cloak General Korrd wore in . Both roles were played by Charles Cooper.
 The captain's dining room is seen for the first time.
 Kahlest tells Picard that Mogh "was loyal to the emperor." However,  will later establish that the Klingons haven't had an emperor in 300 years. It can be assumed that Kahlest was abstractly referring to the Emperor Kahless and his guiding principles for all Klingons.
 This is the only episode where Duras' father Ja'rod is actually named.
 Picard refers to the Klingon state as the "Klingon Imperial Empire," a redundant designation which was never used again.
 On the medical file for Kahlest, Dr. Crusher reads that she was treated at Starbase 24. However, the okudagram reads Starbase 23.
 This is the first episode to acknowledge Dr. Crusher's middle initial, 'C'.
 Michael Dorn accidentally flubs the Klingon word Ha'DIbaH (animal). He transposes two syllables and says "ha'bidah" instead. Patrick Massett makes the same error later in .

Reception 
 Entertainment Weekly ranked this episode #7 in their list of "The Top 10 Episodes" to celebrate the 20th anniversary of Star Trek: The Next Generation. 
 This episode won an Emmy Award for Outstanding Art Direction for a Series.
 Michael Piller commented, "It was complicated, because we were combining characters and scripts, trying to put together a Worf story we liked. I think we came out of it fairly well, with a good show." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 193)
 Moore remarked, "I thought Tony Todd did a wonderful job as Worf's brother. I was kind of worried, because there's always that hesitation when you're bringing in other family members no one else has even seen. Half the audience is ready to throw things at the screen, and you're thinking, 'This better work.' I was there when he stepped on the stage and made it his own." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 193)
 Moore saw this episode as a turning point towards more continuing story arcs on The Next Generation. He commented, "The biggest decision on this show was the ending…where Worf takes it on the chin and decides to accept his dishonor even though he knows it's a lie but he does it for the greater glory of the Empire and he walks out the door and it ends with this sense of 'Oh my God. This has changed Worf forever, and what's going to happen to him next?' And what that did to the franchise overall was it suddenly said there's a continuing story here…As soon as Worf walks out the door with his dishonor it demands a follow-up. And that's why we eventually came back to  and  and on and on and on. All the Worf stories spring from that moment, and also opened up the whole franchise to the idea that maybe we can do continuing stories. It was really a pivotal moment looking back on how we structured Next Generation." (Chronicles from the Final Frontier, TNG Season 4 DVD special features)
 Michael Dorn observed, "There was a lot more involved in it than the writers realized. Things that have to do with Klingon loyalty and honor. They didn't give it its due. You look at Worf in a different light, and I've played him in a different light since that episode. This is not something they have come up with. I'm doing this on my own. Hey, it's their fault. They wrote it. So now, I'm going to carry on with it." (Captains' Logs: The Unauthorized Complete Trek Voyages, pp. 193–194)
 The book Star Trek 101 (p. 72), by Terry J. Erdmann and Paula M. Block, lists this episode as one of the "Ten Essential Episodes" from Star Trek: The Next Generation.
 A mission report for this episode by Patrick Daniel O'Neill was published in .

Remastered version 

The episode was one of three selected for inclusion in the Star Trek: The Next Generation - The Next Level sampler disc intended as a preview of the remastering process for The Next Generation. Amongst the adaptations required to bring the episode up to high-definition quality included a restaging of the opening shot as a digital matte painting, and a new image of Qo'noS by Max Gabl (as the original was output directly to videotape using  and did not exist as a film element). 

One complication arose with this episode: thirteen seconds of the original film negative – the first part of the scene in Act Four where Crusher and Riker discuss the discovery of the additional survivor, Kahlest – could not be located. As a result, this sequence had to be upgraded from the standard definition master tape.  On 11 April 2012 director Robert Meyer Burnett confirmed that the missing thirteen seconds were located and will be included in the TNG Season 3 Blu-ray,  and a preview of the fully-restored scene was included in the TNG Season 1 Blu-ray bonus features.

Video and DVD releases
 Original UK VHS release (two-episode tapes, CIC Video): Volume 33, catalog number VHR 2560, 
 UK re-release (three-episode tapes, Paramount Home Entertainment): Volume 3.6, 
 As part of the TNG Season 3 DVD collection
 As part of the Star Trek: Fan Collective - Klingon collection
 As part of the Star Trek: The Next Generation - The Next Level Blu-Ray collection
 As part of the TNG Season 3 Blu-ray collection

Links and references

Starring 
 Patrick Stewart as Capt. Jean-Luc Picard
 Jonathan Frakes as Commander William Riker

Also starring 
 LeVar Burton as Lt. Cmdr. Geordi La Forge
 Michael Dorn as Lieutenant Worf
 Gates McFadden as Dr. Beverly Crusher
 Marina Sirtis as Counselor Deanna Troi
 Brent Spiner as Lt. Commander Data
 Wil Wheaton as Wesley Crusher

Guest stars 
 Charles Cooper as K'mpec
 Tony Todd as Kurn
 Patrick Massett as Duras
 Thelma Lee as Kahlest

Co-star 
 Teddy Davis as Transporter Tech

Uncredited co-stars 
 Rachen Assapiomonwait as 
 Majel Barrett as  computer voice
 Michael Braveheart as Martinez
 B.J. Davis as Klingon assassin
 Chris Doyle as Klingon assassin
 Eben Ham as Klingon Council member
 Kim as operations division officer
 Mark Lentry as science division officer
 Debbie Marsh as command division ensign
 James McElroy as command division officer
 John Rice as science division officer
 Joseph Michael Roth as Klingon High Council member
 Guy Vardaman as
 Darien Wallace
 Klingon High Council member
 Mark Wilson as Klingon High Council member
 Natalie Wood as Bailey
 Unknown performers as
 Command division officer
 Command division officer
 Command division officer
 Command division officer
 Female civilian
 Female command division officer
 Female engineer
 Female operations division ensign
 Female operations division officer
 Female science division officer
 Operations division officer
 Security officer
 Seven Klingon citizens
 Ten Forward waiter
 Ten Forward waitress
 Ten Klingon High Council members

Stunt doubles 
 John Nowak as stunt double for Patrick Stewart
 Unknown stunt performer as stunt double for Tony Todd

Stand-ins 
 Jeffrey Deacon – stand-in for Patrick Stewart
 Nora Leonhardt – stand-in for Marina Sirtis
 Tim McCormack – stand-in for Brent Spiner
 Lorine Mendell – stand-in for Gates McFadden
 Guy Vardaman – stand-in for Wil Wheaton

References 
2345; 2346; 2366; 26th century; "a bit"; accusation; ; admiration; "after all"; Age of Ascension; aiding and abetting; "all right"; allegation; alliance; "an iron hand"; "and then some"; assassin; assignment; assumption; asteroid; asteroid field; "at all"; "at ease"; "at stake"; "at the time"; attack; authority; "back up"; bearing; ; bird; birthright; blood; bloodline; brother; "by all means"; capital crime; captain's mess; ; Caspian Sea; caviar; cha'DIch; ; chief medical officer; choice; civil war; combat; commander; cometary cloud; comfort; commanding officer;  computer; coordinates; council; council chamber; course; coward; "credit to"; crime; cross reference; cruiser; culture; curiosity; death; deception; defense access code; delicacy; ; destruction; discipline; discomfort; discommendation; ; dishonor; distress call; dog; dust; Earth; egg; emblem; enemy; environment; evidence; execution; experience; family; family name; fear; Federation; file; First City; first officer; first officer's position; fish; flight path; food; fool; friend; generation; gesture; ghojmoK; "go ahead"; Great Hall; ; heart; heritage; history; home; honor; hour; house; House of Duras; House of Mogh; Human; "I do not know"; impulse power; "in that regard"; "in the middle of"; information; innocence; inspection; intention; ; Ja'rod; ; "jumps down my throat"; "keep your place"; Khitomer; Khitomer commander; Khitomer Massacre; Khitomer Massacre victims; Khitomer Outpost; kilometer; Klingon; Klingon Bird-of-Prey (Kurn's transferring ship); Klingon Central information net; Klingon custom; Klingon Defense Force; Klingon emperor; Klingon food; Klingon High Command; Klingon High Council; Klingon Imperial Empire; Klingon law; Klingonese; knowledge; kut'luch; leave of absence; lie; Lorgh; madam; maintenance cycle; meat; medical record; mek'ba; menu; ; mister; Mogh; Mogh's wife; name; nurse; obedience; object; "of course"; Officer Exchange Program; Old Quarter; "on board"; "on the scene"; opportunity; order; outsider; ; permission; personal security code; personnel; place; polite; problem; protocol; punishment; Qo'noS; quarters; question; range; recess; region; relative; relaxation; replicator; reputation; rescue vessel; respect; revenge; right; risk; Romulan; Romulan patrol ship; ; second; secret; sensor; sensor scan; sensor log; sensor range; service record; shame; shield; shift; sir; "so be it"; son; "stand by"; Starbase 24; Starfleet; Starfleet regulations; station; status quo; stomach; style of command; subspace transmission; suggestion; sun; survivor; tactics; taste; thousand; threat; timebase; tolerance; tour; traitor; trap; treachery; treatment; trust; truth; turkey; turn; value; "very well"; visit; "wait a second"; warrior; weapon; "well done"; wisdom; wish; witness; word; wound; year

Other references 
 Starfleet Mission Archives Database: ; casualty; civilian; communications traffic; distance; investigation; Khitomer system; light hour; orbital bombardment; percent; planetary defenses; rescue mission; science ops; sector containing Khitomer system; spacecraft; standard orbit; Starfleet Command; tactical communications; 
 USS Intrepid Medical Mission Files: biomedical facility; chief medical officer; Klingon consulate; medical facility; Moran; patient; stable condition; Starbase 23; Theta Amano Trade Center

External links 
 
 
 
 

de:Die Sünden des Vaters
es:Sins of the Father
fr:Sins of the Father (épisode)
ja:汚名～クリンゴン戦士として～（エピソード）
nl:Sins of the Father
pl:Sins of the Father
TNG episodes