Dagger of the Mind (episode)
A routine visit to the Tantalus Penal Colony proves dangerous for Kirk and an Enterprise psychiatrist.

Summary

Teaser
The  is on a routine cargo drop to the Tantalus Penal Colony on the planet Tantalus V, beaming down cylinders containing infra-sensory drugs and other supplies. Lieutenant Berkley, in charge of the transporter, tries to beam the cargo down, but is having trouble doing so. Captain Kirk enters the transporter room seeing this and jokingly chides Berkley over the fact that the colony has not yet deactivated its security force field. After contacting the colony, it does so and the cargo is beamed down. The colony sends up a large case to the Enterprise, which is research supplies for the Central Bureau of Penology at Stockholm. After Kirk and Berkley leave, the case opens slowly, revealing a man, clearly mentally ill. He carefully makes his way towards the distracted assistant transporter operator, knocking him out.

Act One
On the bridge, Kirk talks to Dr. McCoy, telling him that he wishes he could have had the time to meet Dr. Tristan Adams, and asks McCoy if he has visited a penal colony since they have started following his theories. "A cage is a cage, Jim," he remarks. Kirk tells McCoy he is behind the times, as the captain considers them to be more like resorts now. Just then, the Tantalus Penal Colony hails the Enterprise, informing the starship that an inmate is missing, and possibly hid in the case they had sent up. They also inform them that the missing patient is a potentially violent case.

Meanwhile, the mysterious stowaway has taken the transporter operator's operations red utility uniform and makes his way out into the Enterprises corridors. He is immediately spotted by Fields, who alerts the bridge through an intercom that he is on deck fourteen. Spock reports that deck fourteen is being closed off and a search is in progress. 

Security is then alerted to the stowaway and he surprises one of the guards looking for him, overpowers him, and takes his phaser. He then heads to the bridge where he easily dispatches the bridge guard and then reveals his name is Simon Van Gelder and he demands asylum from Kirk. After he is incapacitated by Spock using a Vulcan nerve pinch, he is captured and restrained in sickbay. Later, Kirk attempts to get answers out of Van Gelder, but he seems to struggle enormously when he tries to confirm his name and that he was a director at the Tantalus colony. McCoy then has him sedated with a hypospray. Later on the bridge, Spock determines that Van Gelder is indeed a former associate of Tantalus administrator Dr. Tristan Adams, assigned to the colony only six months prior. 

Required by regulations as quoted by McCoy to investigate Van Gelder's injury, Kirk decides to visit the penal colony with someone who has psychiatric experience.

Act Two

The Enterprise has returned to Tantalus V and assumed standard orbit. Kirk enters the transporter room with Spock and is surprised to discover that he is beaming down to Tantalus V with Doctor Helen Noel, a psychiatrist with whom he's been previously acquainted. In the transporter room, she tries to remind Kirk about their previous encounter, but he cuts her off.  Spock asks if the Captain has a problem, to which Kirk replies, telling Spock to let Dr. McCoy know that Dr. Noel better be his best technical aide.  After beaming down, Kirk and Noel take a very fast turbolift down to the colony.  Adams meets with the two immediately after the doors open shares a toast in his office with them. Just then, Lethe, an emotionally detached former patient at the colony and now therapist enters. "I love my work," she says unenthusiastically. Adams raises his glass to Kirk and Noel for the toast. "To all mankind. May we never find space so vast, planets so cold, heart and mind so empty that – that we cannot fill them with love and warmth."

Later, walking through the corridors of the colony, Dr. Adams informs Kirk and Noel that Van Gelder injured his mind by testing an experimental therapy device on himself, the neural neutralizer. Adams shows the device in operation on a patient, but says that it is of limited therapeutic value.

On board the Enterprise, Spock and Dr. McCoy continue to investigate Van Gelder, whose ravings are difficult to decipher. However, at one point, Van Gelder claims Dr. Adams will destroy "like death".

Act Three

In sickbay, Spock decides to employ an ancient technique, the Vulcan mind meld, to learn the truth that Van Gelder cannot speak aloud. Although Spock had never previously performed a mind meld on a Human, the procedure meets with some success. He learns that Adams has been experimenting on various individuals, including Van Gelder, using the neural neutralizer.

At the colony, Kirk and Noel investigate the neural neutralizer privately. Kirk wants first-hand experience with the device. After Noel provides assurance that an experiment can be done safely with her supervision, Kirk sits in the treatment chair. Using a very low setting, she suggests to Kirk that he is hungry. A few seconds later, unaware of the suggestion, Kirk does in fact suggest they find a kitchen to raid. Then, at Kirk's request, Noel begins with a more elaborate suggestion; that Kirk and Noel went back to Kirk's quarters for a romantic evening after a meeting at the previous year's science lab's Christmas party, which didn't really occur. Suddenly, Adams surprises them, has his assistant  immobilize Noel, and begins using the device to condition Kirk, including the suggestion that he is desperately in love with Noel, and using very high settings that are obviously causing Kirk great distress.

Act Four
Fighting off the suggestions placed in his mind by Adams, Kirk dispatches Noel through the air conditioning ducts, in the hope she can find the power controls and deactivate the security force field. That field protects the facility, and prevents transporters from operating in it. After crawling through the duct, Noel manages to locate the power control room for the colony. She takes care of the guard in the power control room and deactivates the field long enough for Kirk to escape the torture, and Spock and a security force to beam down and secure the colony.

In an ironic twist, Dr. Adams dies of exposure to the neural neutralizer after Kirk knocks him down and leaves him near it when Spock restored the power. However, Dr. Noel notes the neutralizer was not on high enough to kill Adams. Kirk says he died because he was alone, his mind emptied by it, "without even a tormentor for company." Dr. Van Gelder is cured, and resumes his responsibilities at the colony. He also dismantles and destroys the neural neutralizer equipment. Before the Enterprise heads away from Tantalus V, McCoy says, "It's hard to believe that a man could die of loneliness." Kirk tells him, "Not when you've sat in that room." He then instructs Spock to break orbit and proceed away at warp factor one.

Log entries 
 Captain's log, USS Enterprise (NCC-1701), 2266
 Ship's log, USS Enterprise (NCC-1701)

Memorable quotes 
"A cage is a cage, Jim."
 - McCoy, on penal colonies

"Interesting. Your Earth people glorify organized violence for forty centuries, but you imprison those who employ it privately."
 - Spock, to McCoy

"Where there is no emotion, there is no motive for violence."
 - Spock, to McCoy

"It appears we may have an inmate of yours aboard the ship."
"Transporter crewman found unconscious, captain. Cargo case open and empty."
"Make that definite, doctor. He's aboard."
 - Kirk and Uhura confirm that Van Gelder is on board the Enterprise to Adams

"I want asylum."
"At gunpoint?"
 - Van Gelder and Kirk, as Van Gelder storms into the bridge 

"You smart, button-pushing brass hat! Wash your hands of it! Is that your system?"
 - Van Gelder to Kirk, in sickbay

"May we never find space so vast, planets so cold, heart and mind so empty that, that we cannot fill them with love and warmth."
 - Adams, toasting with Kirk and Noel 

"One of the advantages of being a captain, doctor, is being able to ask for advice without necessarily having to take it."
 - Kirk, to Noel

"You begin to feel a strange euphoria. Your body floats."
 - Spock, performing his first mind-meld on a Human

"I have no desire to damage my brain. Can this be handled with reasonable safety – yes or no?"
 - Kirk, to Helen Noel on the neural neutralizer

"It's hard to believe that a man could die of loneliness."
"Not when you've sat in that room."
 - McCoy and Kirk, on the death of Doctor Adams

Background information

Production timeline 
 Story outline by Shimon Wincelberg: mid-
 Revised story outline: 
 Second revised story outline: 
 Third revised story outline: 
 Fourth revised story outline: 
 First draft teleplay: early-
 Second draft teleplay: 
 Revised second draft teleplay: 
 Revised teleplay by John D.F. Black: 
 Revised teleplay by Gene Roddenberry: 
 Additional revisions: 
 Final draft teleplay by Roddenberry: 
 Additional revisions: 
 Revised final draft teleplay: 
 Additional revisions: , , 
 Filmed:  – 
 Day 1 – , Tuesday (Half Day) – Desilu Stage 9: Int. Bridge
 Day 2 – , Wednesday – Desilu Stage 9: Int. Bridge, Transporter room
 Day 3 – , Thursday – Desilu Stage 9: Int. Transporter room, Corridors, Kirk's quarters, Sickbay
 Day 4 – , Friday – Desilu Stage 9: Int. Sickbay, Tantalus Colony Main power chamber
 Day 5 – , Monday – Desilu Stage 10: Int. Dr. Adams' office, Kirk's guestroom, Dr. Noel's guestroom, Air vents
 Day 6 – , Tuesday – Desilu Stage 10: Int. Tantalus colony corridors, Treatment room
 Day 7 – , Wednesday – Desilu Stage 10: Int. Treatment room
 Extra pickup shots filmed – , Thursday 
 Original airdate: 
 First UK airdate:

Production
 Writer S. Bar-David is a pen name for Shimon Wincelberg. He incorporated several references to Jewish parables into the screenplay.
 The part of Helen Noel was originally written for Grace Lee Whitney's character Janice Rand; however, producers wanted to avoid showing Kirk becoming involved with her, and Whitney was already on the verge of leaving the show due to personal problems on the set. (The Star Trek Compendium) 
 The title of this episode is taken from a line of Shakespeare's play, Macbeth. This is the first of a great many episodes in the franchise to take its title from a quotation from Shakespeare. In the context of this quotation, Macbeth is preparing to murder Duncan, the King of Scotland, and sees a dagger that he attempts to grasp, only to discover it is a figment of his imagination. The relevant passage from the soliloquy reads:
Is this a dagger which I see before me
The handle toward my hand? Come, let me clutch thee.
I have thee not, and yet I see thee still
Art thou not, fatal vision, sensible
To feeling as to sight? Or art thou but
A dagger of the mind, a false creation
Proceeding from the heat-oppressèd brain?
 The name "Lethe" is a reference to the River of Forgetfulness in Greek mythology. (These Are the Voyages: TOS Season One, 1st ed. p. 234)
 The name of the colony, Tantalus, is also a reference to Greek mythology. Tantalus was a former king imprisoned in Tartarus for various evil deeds. Tantalus was forever chin deep in water, and fruit-laden branches hung within easy reach. But when he tried to eat or drink the fruit and water receded from him so that he could not. (These Are the Voyages: TOS Season One, 1st ed. p. 234)
 The shot of the Enterprise miniature heading back to Tantalus at the beginning of Act Two does not appear in any other episode. The ship shifts slightly before veering out of frame; when this shot is used in other episodes, the model merely veers off.
 The producers still hadn't settled on background sound effects for the bridge when this episode was produced. Both the older bridge sound effect (first heard in ) and the familiar whirring sound that eventually would became standard were used in this episode.

Cast
 James Doohan (Scott) and George Takei (Sulu) do not appear in this episode.
 Scott appeared in the original script, operating the transporter in the first scene, when Van Gelder is beamed aboard. His appearance was nixed by Bob Justman, who saw this as a way of saving costs by eliminating Doohan – who would have been paid US$890 for the episode – and replacing him with a random performer (Larry Anthony, playing Lieutenant Berkley), hired for a much lower salary. (These Are the Voyages: TOS Season One, 1st ed. p. 237)
 After finishing this episode, Morgan Woodward (playing the emotionally and physically intense role of Van Gelder) reportedly went home and took a rest for four days.

Sets and props
 The chair used in the neural neutralizer room was later re-used by Garth in .
 Albert Whitlock's matte painting for  is recycled here, with the towers on the fuel bins painted out and a different doorway added to match with the live-action footage filmed of Kirk and Noel entering the surface shaft. This was made as a compromise between Gene Roddenberry and Bob Justman. Roddenberry wanted Kirk and Noel to arrive on the surface, then go underground via the elevator, while Justman urged him to eliminate this scene, and let them beam down directly into Dr. Adams' office (thus saving the costs of creating a matte painting and some extra sets). Roddenberry kept the surface scene in, but reused the old matte painting created for the second pilot. (These Are the Voyages: TOS Season One, 1st ed. p. 241)
 Some of the colony interiors are reused (and redressed) sets left over from the previous episode, . (These Are the Voyages: TOS Season One, 1st ed. p. 242)

Costumes
 The treatment smocks worn by Adams and Eli have the same insignia as Dr. Cory in .

Continuity
 This episode is mentioned as taking place after a Christmas party in the science labs. This is one of the few times a religious holiday is mentioned in the Star Trek future, and Christmas in particular was not mentioned again until . Similarly,  references Thanksgiving, and  references Halloween.
 This episode marks the first appearance of the Vulcan mind meld. The final shooting draft of this script had Spock placing his hands on Van Gelder's abdomen while performing the mind meld. According to The Making of Star Trek, the mind meld was developed as an alternative to the scripts use of hypnosis to stabilize Van Gelder. They did not want to inaccurately depict hypnosis as a medical technique. Nor did they want to shoehorn into the script a pretext that Spock was qualified to act as a hypnotist in a medical capacity. Lastly, they did not want to risk accidentally hypnotizing viewers at home.
 A shipping label produced for  shows that a (now elderly) Dr. Van Gelder is still in charge of the Tantalus Penal Colony in the 2370s.
The name of the penal colony in this episode, "Tantalus," was reused in Season 2 for the episode "Mirror, Mirror" for a surveillance and killing device known as the Tantalus field.

Preview 
 The preview contains a truncated Captain's Log from the finished episode: "Captain's log, stardate 2715.1. Exchanged cargo with penal colony on Tantalus 5."

Syndication cuts 
During the syndication run of Star Trek, the following scenes were typically cut from broadcast

 A log entry by Kirk in which he recaps the situation of Van Gelder's escape and then states that he (Kirk) will get to meet Doctor Adams after all.
 A log entry by Spock in which he explains the Vulcan mind meld in some detail.  While the mind meld later became a common plot device, at this early stage of Star Trek production, the viewing audience had not yet seen the meld on camera, leading to Spock's need to explain the nature of the meld.  When the episode was syndicated, this scene was frequently cut, since it was assumed that most viewers already knew what the mind meld was.
 A more lengthy recovery scene by Kirk after his first neural neutralizer session.

Video and DVD releases 
Original US Betamax release: 
Original UK VHS release (two-episode tapes, CIC Video): Volume 6, catalog number VHR 2253, release date unknown
US VHS release: 
UK re-release (three-episode tapes, CIC Video): Volume 1.4, 
Original US DVD release (single-disc): Volume 5, 
As part of the TOS Season 1 DVD collection
As part of the TOS Season 1 HD DVD collection
 As part of the TOS Season 1 Blu-ray collection

Links and references

Starring 
 William Shatner as Capt. Kirk

Also starring 
 Leonard Nimoy as Mr. Spock

Guest star 
 James Gregory as Tristan Adams

Co-starring 
 DeForest Kelley as Leonard McCoy
 Morgan Woodward as Simon Van Gelder
And
 Marianna Hill as Helen Noel

Featuring 
 Nichelle Nichols as Uhura
 Susanne Wasson as Lethe
 John Arndt as First Crewman
 Larry Anthony as Transportation Man 
 Ed McCready as Inmate
 Eli Behar as

Uncredited co-stars 
 Frank da Vinci as Vinci
 Lou Elias as Therapist
 Ron Kinwald as Inmate
 Jeannie Malone as Inmate
 John Hugh McKnight as Therapist
 Eddie Paskey as Leslie
 Unknown actors as
 Karl
 Helmsman
 Navigator
 Security Crewman 1
 Security Crewman 3
 Transporter Crewman
 Inmates 4, 5, 6 & 7
 Therapist 1 & 2

Stand-ins
William Blackburn as the stand-in for DeForest Kelley
Frank da Vinci as the stand-in for Leonard Nimoy
Jeannie Malone as the stand-in for Marianna Hill
Eddie Paskey as the stand-in for William Shatner

References 
2nd millennium BC; 2220s; 2246; 2265; 2266; acting captain; ; advice; afternoon; agony; air conditioning; "all right"; answer; area; assignment; assistant; associate; assumption; asylum; ball; beam neutralizing; bloodstream; blood vessel; body; body function panel; "Bones"; box; brain neutralizing beam; brain wave; brass hat; briefing room; ; cabin; cage; captain's log; career; cargo; cargo case; case; casualty; Central Bureau of Penology; chance; chair; Chamber of Horrors; Christmas; Christmas party; Christmas present; colony; Constitition-class decks; contact; control panel; coordinates; course; crime; criminal; cure; damage; dancing; danger; day; death; delusions; ; ; desire; destination; device; Devil's Island; director; door; dose; duct; Earth; effect; electronic clipboard; elevator; Emergency Channel D; emotion; engineering uniform; estimate; euphoria; Eurasia; "excuse me"; experiment; face; fact; failure; floor; foot (appendage);  (unit); force field; general quarters; general quarters 3; hailing frequency; hand; happy; hate; heart; honesty; ; hospital facility; hour; Human; hunger; hyper-power circuit; hypnosis; hypo; identification tape (aka ID tape); "in case"; infra-sensory drugs; injury; "in progress"; instruction; intruder; intruder alert; investigation; kitchen; knee; library; lie; light; location; loneliness; love; machine; Manual on Penal Colony procedures; medical log; medikit; megavoltage; memory; memory patterns; "Merry Christmas"; mind; mind meld; minute; mission; mistake; month; morning; motive; naked; name; nerve; neural neutralizer; neuro-synapse; night; off-on switch; "on the nose"; over-changer; oxygen mask; pain; party; patient; penal colony (aka rehab colony); penology; person; personnel director; phaser weapon; place; planet; ; power supply; prisoner (aka inmate); problem; profession; promise; psychiatrist; psychiatry; psychotherapy; quarters; question; rehabilitative therapy; report; reputation; resort colony; room; sage; sage and skeptic; science lab; Science Library; schizophrenia; search; second; second-in-command; secrecy; section; security alert (aka security alert 3 / security alert, condition three / alert condition three); security screen (aka security cover/security force field); sedative; sharing; ship's library; ship surgeon/ship's surgeon; short circuit; skeptic; sobbing; space; speaker; specimen; sponge; standard orbit; "stand by"; star; starship regulation; Stockholm; stubborn; study; suggestion; Tantalus V; Tantalus Penal Colony (aka Tantalus Penal Colony); technical aide (aka technical expert); theory; therapist; thing; thought; tissue; title; toast; towel; tranquilizers; treatment; treatment room; truth; tunnel; unscientific‎; vault; violence; Vulcan; Vulcan neck pinch; wisdom; word; wrap

Unreferenced materials 
amen; brain pattern; brandy; cat; delta waves; Feinberg; Finnerman; Merhoff; scimitar; small white pill; stencil; Voice-O-Graph projections

External links 
 
 
 
 

de:Der Zentralnervensystemmanipulator
es:Dagger of the Mind
fr:Dagger of the Mind (épisode)
it:Trasmissione di pensiero (episodio)
ja:悪魔島から来た狂人（エピソード）
nl:Dagger of the Mind
pl:Dagger of the Mind
pt:Dagger of the Mind
ru:Кинжал разума (эпизод)
sv:Dagger of the Mind
TOS episodes