Conundrum (episode)
After the crew's memories are mysteriously erased, the computer records indicate that the Federation is at war with the Lysians, and that the Enterprise has been ordered to attack their command center.

Summary

Teaser 
"Captain's log, Stardate 45494.2. We're investigating a series of subspace signals that may indicate intelligent life in the Epsilon Silar system. We are within sensor range."

As the crew is going through a typical day, with Data in Ten Forward fixing Deanna Troi a Samarian sunset done in the traditional style to settle a bet over a three-dimensional chess game, Dr. Beverly Crusher tending to Kristin, a crewmember injured while cliff-diving on the holodeck, and Commander Riker arguing with Ensign Ro about her changing ship's procedure without his knowledge, the  is approached by a small vessel of unknown configuration. After the vessel initiates an intense scan of the Enterprise, a wave of green energy passes throughout the ship, and the entire crew suffers from memory loss.

Act One 
The crewmembers have forgotten their identities but have retained their appropriate skills for running the ship. What they also don't realize is that there is someone else on the bridge who wasn't there before the wave hit, also wearing a  and claiming to be suffering from memory loss.

While trying to ascertain who they are and why they are on this starship, Riker suggests to an equally anonymous Captain Picard that he is their leader, since he has four pips on his collar, more than anyone else present. Worf suggests otherwise, and presumes he is the leader because he is the most decorated person on board due to his baldric. Dr. Crusher realizes that she is a medical officer, but the injured crewmember in sickbay still doesn't know what she is doing there. Riker, Ro, and La Forge go to engineering to try to get the engines running. La Forge works on getting propulsion back online and tries to find personnel files so that they'll know who they are while Riker and Ro go to the rest of the ship as a survey team. Worf, in the meantime, has assumed leadership and is happy when La Forge reports the ship is ready for battle with the navigation, propulsion, weapons, and communications back online.

Act Two 
With computer access limited, Riker and Ro travel throughout the ship and confirm that the memory loss is not limited only to the bridge; rather than their normal hostility, the two have an almost playful relationship, with Ro commenting that Riker doesn't look like someone who needs a holodeck to have fun. 

After La Forge successfully accesses the ship's computer, he is able to get a list with photos of the Enterprises bridge officers. The list confirms that Picard is indeed the commanding officer of the Enterprise. To Worf's dismay, the list has him near the bottom, second to last; he apologizes to Picard for asserting authority where he had none, but Picard tells him to think nothing more of it. Interestingly, the computer's list has one new addition to the ship's regular command crew. Commander Kieran MacDuff is the ship's first officer, and Commander Riker has been bumped down to second officer.

Data and La Forge are able to get more information out of the computer, and they brief the senior officers about their current mission: The Enterprise has been tasked to destroy the Lysian command center as part of a coordinated attack on their mortal enemy, with whom the Federation has been at war for years. The information also suggests that the Lysians have a new weapon which could cause memory loss. Troi wants to open communications with headquarters to confirm their mission, but the Enterprises orders include radio silence at all times. Picard orders MacDuff to set a course towards the Lysian command center. Troi doesn't like it.

Act Three 
Troi has a strong feeling that the war is wrong but can't pin down a reason, and Riker suggests it is just due to the general nature of war. When Riker returns to his quarters, he finds Ro lounging in a chair waiting for him. Ro tells Riker that they could be married, and Riker tells it is also equally possible that they hate each other. They begin to lie down on Riker's bed and Riker asks her what if he snores in his sleep. Ro responds by asking him what makes him think he is going to get any sleep tonight.

As the Enterprise crosses into Lysian space, a Lysian destroyer tries to hail the Enterprise. Picard wants to open a channel, but MacDuff suggests that that may be how they lost their memories to begin with. The Lysian destroyer starts to fire at the Enterprise, but the starship is able to easily destroy the Lysian vessel – too easily. MacDuff congratulates Picard for his decisiveness, but the captain is bothered by how ineffective the Lysian's defenses were.

Act Four 

Troi also inexplicably feels that Riker is very "familiar"; the two realize they have some connection when he finds a book, Ode to Psyche by John Keats, which she gave him as a gift "with love", producing a rather awkward moment when Ro arrives and sees them nearly kissing before she kisses Riker herself once Troi leaves. Ro informs Riker that she gets the feeling she used to be the jealous type before giving him a kiss.

Efforts to repair the memory loss have been limited, as La Forge cannot gain access to more detailed personnel files or medical records that might allow Dr. Crusher to safely attempt to restore the crew's memories; MacDuff volunteers despite the risks, but Crusher stops her efforts when he apparently begins having seizures, missing MacDuff's slight sinister smile as she walks away. 

Picard wonders if the Federation is truly at war with such a technologically inferior enemy. He feels a moral dilemma, comparing his situation to being given a weapon and told to go into a room to kill a stranger but still wanting to know why; MacDuff counters that it would be wrong to allow the war to continue and claim millions of lives just because Picard is experiencing moral qualms. MacDuff has a private conversation with Worf, his fellow warrior, and warns him there might be a situation where a split-second decision may need to be made, even if Picard has not yet given the orders to do so.

Act Five 

The Enterprise arrives in the Lysian system and proceed towards the Lysian Central Command, where it is intercepted by 47 unmanned Lysian sentry pods. These vessels are easily destroyed, and the Enterprise continues on to the command center. Data informs Picard that the Lysian command center is virtually defenseless with 15,311 people aboard. One photon torpedo could destroy the entire structure, while its entire arsenal could not even damage the Enterprise. Troi again insists the situation is wrong, and Riker poses the question: How could the Federation's mortal enemy be over a hundred years behind it in weapons technology? MacDuff insists that Picard destroy the station, but Picard refuses to fire on defenseless people and instead tells Worf to open a channel. MacDuff tells Worf belay the order and declares that something is wrong with the captain and attempts to assume command, giving Worf an order to fire all weapons. When Worf refuses, MacDuff knocks him away with surprising force and tries to fire himself. Riker shoots him with a phaser. The beam knocks MacDuff back and reveals a shocking fact; he is not Human. Worf and Riker then combine their phaser shots to knock MacDuff to the floor and subdue him.

"Captain's log, supplemental. We are on a course to Starbase 310. Dr. Crusher has been working steadily and has restored the memories of most of the crew."

Determining that there was an artificial effect suppressing the crew's memories, Dr. Crusher works to quickly restore them. MacDuff is identified as a Satarran, a race which has been at war with the Lysians for decades. Despite their skill with memory suppression, the Satarrans lacked sophisticated weapons technology, and so had plotted to hijack the Enterprise and tilt the war in their favor. Picard apologized on behalf of the Federation for the deaths of the Lysian destroyer's crew. With MacDuff's plan foiled, the Enterprise heads off to its next assignment – although Riker remains uneasy when he encounters Troi and Ro intensely conversing in Ten Forward. Ro insists somewhat facetiously that they have a memory they will both treasure; Troi concludes that such actions tend to result from subconscious desires. When Riker concedes confusion, she smiles and assures him that "if you're still confused tomorrow, you know where my office is."

Log entries 
 Captain's log, USS Enterprise (NCC-1701-D), 2368

Memorable quotes 
"Data, chess isn't just a game of ploys and gambits; it's a game of intuition."
"Hmm. You are a challenging opponent, Counselor."
 - Troi, after defeating Data at a game of chess in Ten Forward

"I don't know who any of you are."
"Nor do I. I don't… I don't even remember who I am."
 - Riker and Picard, on the bridge after having their memories blocked

"It looks like I'm the pilot."
 - Ro Laren

(To Picard) "Looks like you're the leader."
(Picard counts his pips.)
"Perhaps we should not jump to conclusions." (Worf points to his baldric) "I am decorated as well."
 - Riker and Worf, trying to determine the leader after Riker counts his pips

"We're going to search the ship."
"Very well. Proceed."
 - Riker and Worf

(Data pops up from behind the bar's counter.) 
"Can I get you something? A beverage?"
 - Data to Riker, Ro, and Troi in Ten Forward

"Contact the operations officer to assist you."
"He's in Ten Forward, waiting tables."
 - Picard and Ro, on Data

"For all we know, you and I could be married."
"For all we know, you and I could hate each other."
 - Riker and Ro

"You must've been one hell of a bartender."
 - La Forge, commenting on the speed at which Data moves

"We must attack!!!"
"I do not fire on defenseless people."
 - "MacDuff" and Picard, realizing once and for all what's going on isn't right

"Commander, don't worry about it. As far as I'm concerned, you and I have shared something that we will treasure forever."
 - Ro, to Riker on their brief relationship

Background information

Production history 
 Ronald D. Moore relays pitch to Michael Piller:  
 In a memo to Rick Berman, David Livingston approves of pitch: 23 April 1990 
 Final draft script:  
 Filmed: 18 November 1991 – 26 November 1991
 Second unit inserts filmed: 
 Premiere airdate: 
 First UK airdate:

Story and script 
 The original pitch involved drafting soldiers by rewriting their memories. () A similar story later appeared in the  episode .
 The story was one of several amnesia stories first pitched in Season 4. Two of these were produced ( and ), and this one was held for further development. (; Captains' Logs: The Unauthorized Complete Trek Voyages, pp. 237-238)
 The majority of this episode's teleplay was in fact written by an uncredited Joe Menosky. According to Brannon Braga, the story went through a number of writers before Menosky made it work. (Captains' Logs: The Unauthorized Complete Trek Voyages, pp. 237-238)
 Rick Berman commented, "It's based on that whole concept of what if? If you have nine people who don't know who or what they are, will they find themselves? Will they find the pecking order? Will the captain become the captain?" (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 238)

Production 
 "Conundrum" was filmed between Monday  and Tuesday  on Paramount Stage 8 and Paramount Stage 9. Second unit inserts were filmed on Thursday  on Paramount Stage 8 and 9.
 This episode is a bottle show. (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 238)

Sets and props 
 The Lysian Central Command model was previously used as the Edo God in .
 As a memory-less Ro Laren waits for him in bed, we see that Commander Riker has a horga'hn in his quarters. The horga'hn was first seen in , when Riker asked Captain Picard to acquire a horga'hn for him while the captain vacationed on Risa.
 One of the chess pieces at the beginning of the episode bears a resemblance to the  from .

Continuity 
 As the crew attempts to learn more about their identities from the computer's databanks, a great deal of biographical data of the Enterprise-D crew is presented in the form of computer readouts. See personnel file.
 The tune Riker plays on his trombone is "The Nearness of You" by . He had previously performed this with the holographic jazz band in .
 This episode marks the third time Picard is seen at the helm of the Enterprise during the series. The other times were in  and .

Reception 
 Michael Piller felt that this episode didn't quite do justice to the original pitch. ()
 Rick Berman commented, "It's a thought provoking episode, I thought. Not one of the greats." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 238)
 Ronald D. Moore, Brannon Braga and Jeri Taylor all nominated the Ro Laren / William T. Riker / Deanna Troi triangle as the highlight of the episode. Taylor commented that it "invigorated the relationships and showed another side of Ro in that she plays comedy very nicely." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 237-238)
 However, Braga thought that the mystery around the fake first officer, Kieran MacDuff, didn't work. (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 238)
 Michelle Forbes enjoyed acting in this episode. "It was fun working with Frakes. It's an interesting problem for a character, because you have a very defined character that leans one way. When you have amnesia you wonder if that brings out a side of you that's always wanted to come out. Would you really be comfortable with that? It's an interesting thing." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 237)
 A mission report for this episode, by John Sayers, was published in .

Awards 
 This episode won an Emmy Award for Outstanding Individual Achievement in Special Visual Effects, sharing it in a tie with .

Video and DVD releases 
 Original UK VHS release (two-episode tapes, CIC Video): Volume 57, 
 UK re-release (three-episode tapes, Paramount Home Entertainment): Volume 5.5, 
 As part of the TNG Season 5 DVD collection

Links and references

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

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

Guest stars 
 Erich Anderson as Kieran MacDuff 
 Michelle Forbes as Ro Laren

Co-stars 
 Liz Vassey as Kristin 
 Erick Weiss as Crewman
 Majel Barrett as Computer Voice

Uncredited co-stars 
 Rachen Assapiomonwait as 
 Lena Banks as operations division ensign
 Michael Braveheart as Martinez
 Debbie David as Russell
 Gerard David, Jr. as operations division ensign
 Lanier Edwards as command division ensign
 Gina Gallante as science division officer
 Melba Gonzalez as command officer
 Grace Harrell as operations division officer
 Melanie Hathorn as sciences officer
 Christie Haydon as command division ensign
 Gary Hunter as science division officer
 Kast as command division officer
 Mark Lentry as civilian
 Jay Montalvo as operations division officer
 Michael Moorehead as science division ensign
 Keith Rayve as civilian
 Noriko Suzuki as operations division ensign
 Talbot as Ten Forward waitress
 John Tampoya as command division ensign
 Théyard as science division officer
 Uchizono as civilian
 Christina Wegler Miles as command division ensign
 Unknown actor as Ten Forward waiter

Stunt doubles 
 Chris Doyle as stunt double for Erich Anderson (deleted scene)
 Rusty McClennon as stunt double for Michael Dorn

Stand-ins 
 David Keith Anderson – stand-in for LeVar Burton
 Margaret Flores – stand-in for Michelle Forbes
 Melba Gonzalez – stand-in for Marina Sirtis
 Mark Lentry – stand-in for Erich Anderson and Brent Spiner
 Tim McCormack – stand-in for Brent Spiner, Erich Anderson, and Erick Weiss
 Lorine Mendell – stand-in for Gates McFadden and Michelle Forbes
 Richard Sarstedt – stand-in for Jonathan Frakes
 Terri – stand-in for Liz Vassey and Michelle Forbes
 Dennis Tracy – stand-in for Patrick Stewart
 Guy Vardaman – stand-in for Brent Spiner
 James Washington – stand-in for Michael Dorn

References 
ability; Alaska; analysis; android; arm; armament; artificial lifeform; As You Like It; attack; attack vessel; attitude; authority; bartender; basic system directory; bathing suit; battleship; battle stations; behavior; bioelectric field; biographical listing; boarding party; brain chemistry; brain scan; checkmate; chief engineer; chief medical officer; choice; Cirrus IV; Cliffs of Heaven; cobalt fusion warhead; coincidence; command path discontinuity; commanding officer; communication channel; computer; computer core; computer record; computer system; console; corridor; crew manifest; culture; cure; damage; databank; database; death; debris; decade; deck; diencephalon; diplomacy; diplomat; disruptor; distance; distress signal; doctor; el-Mitra Exchange; Emerald Wading Pool; emotion; enemy; energy wave; engineer; engineering core; Epsilon Silar system; evasive maneuvers (aka evasive action); executive officer; Federation; Federation starships; feeling; file; file wall; firing range; flight handling assessment; flight path; frequency; front; full diagnostic (aka complete diagnostic); fun; fusion; Galaxy-class decks; gambit; genocide; hail; hand; hate; head; helm; helm officer; hesitation; hippocampus; history; holodeck; Holodeck Program 47-C; holographic program; home planet; horga'hn; hour; idea; impulse drive; information; information storage area; injury; intercept course; intuition; jealousy; ; kilometer; kilojoule; ; kiss; knowledge; Kriskov Gambit; laser cannon; leader; leadership; length; lifeform; life support system; ligament; living quarters; locator subroutine; long-term memory; Lysia; Lysians; Lysian Alliance; Lysian battleship; Lysian border; Lysian Central Command; Lysian destroyer (aka Lysian warship); Lysian destroyer crew; Lysian system; Lysian territory; magnetic propulsion; main engineering; marriage; Master of Science; medial temporal; medical file; medical index; medical record; medical specialist; megajoule; memory; meter; military operation; mission; mission report; moral; mountain climbing; musician; navigation; navigator; object; Ode to Psyche; offline; onboard communications system; operations officer; optical data network; order; organization; panic; patient; percent; personnel file; phaser; phaser array; phaser bank; photon torpedo; pilot; plan; plasma; processor; propulsion; pulse laser; question; race; radio silence; record; red alert; representative; Risa; risk; ; rook; room; Samarian sunset; Satarrans; Satarran starship; scanning signal; schematic; science officer; scientist; second officer; security chief; senior officer; sensor range; sensor system; sensor sweep; sentry pod; sequence initiator; sequencing program; shield grid; ship's counselor; short-term memory;shuttlecraft; skill; sleep; snoring; speed; Starbase 301; Starfleet; Starfleet Headquarters; Starfleet records; state of war; status report; ; stranger; subspace interference pattern; subspace radio; subspace signal; Sumiko IV; superior; survey team; swimming; swimming pool; synapse; table; tactical analysis; tactical array; tactical console; tactical control (aka tactical system); tape; three-dimensional chess; throat; torpedo bay; transporter; treatment; trombone; turbolift; turbolift system; vacation; vessel; victory; visual range; voice interface; volunteer; warp drive; warrior; weapon; weapon range; year

Other references 
Personnel files: 2305; 2323; 2324; 2327; 2334; 2334; 2336; 2338; 2340; 2341; 2342; 2345; 2350; 2352; 2355; 2356; 2357; 2358; 2359; 2361; 2362; 2364; Academy of Starfleet Surgeons; Arbiter of Succession; Bajor; Betazed; Copernicus City; court martial; ; Earth; flight control officer; France; Gamma Canaris N; Garon II; ; ; Klingon; La Barre; Lal; Luna; ; ; Omicron Theta colony; ; ; ; probability mechanics; psychology; Ro Gale; Ro Talia; ; Starfleet Academy; ; ; ; 
Engineering Department Status: atmospheric recycle and processing subsystem; celestial timebase reference system; external navigational interferometer; Federation navigational beacon sensor; gravimetric generation and inertial damping subsystem; impulse propulsion system; intraship voice communications net; matter-antimatter reaction assembly; navigational realtime relative timespace monitor sensor; optical data network; thermal integrity; warp field generational nacelle coils; water and solid waste recycling subsystem

Retconned references 
Bajora;

External links 
 
 
 
 

de:Mission ohne Gedächtnis
es:Conundrum
fr:Conundrum (épisode)
it:Amnesia (episodio)
ja:謎めいた記憶喪失（エピソード）
nl:Conundrum
pl:Conundrum
TNG episodes