'Back to Reality' (Red Dwarf V, originally transmitted on BBC2, 26/3/1992

An alien seabed, the far future. The wandering space shuttle Starbug has discovered the remains of the SSS Esperanto, a genetic engineering vessel designed to introduce new and highly evolved life forms into the surrounding environment. Officious second technician Arnold J. Rimmer (a holographic projection of his dead self) remains on board Starbug, while layabout technician Dave Lister and subservient android Kryten explore the Esperanto, along with Cat (a preening humanoid derived from Lister's pet).

They find three long-dead crewmembers and a haddock, all of which evidently committed suicide. Lister discovers traces of an alien slime, which Kryten recognises as hallucinogenic venom secreted by one of the Esperanto's creations, a sea monster known as the 'Despair Squid'. Having fled back to Starbug everyone takes mood-stabilising drugs in order to stem contamination. The Despair Squid returns and ejects a cloud of its toxic ink, causing Starbug to crash and explode.

Waking up in an unfamiliar room, Lister, Rimmer, Kryten and Cat learn that they have just exited a popular video game known as 'Red Dwarf', which they have been playing for the last four years. An engineer appears and points out the clues they all missed in order to complete the game. Rimmer's character was actually a dashing secret agent, while Lister was destined to become a God.

The bewildered players learn their own true identities: Cat is actually a buck-toothed dweeb named Dwayne Dibley and Kryten a cyborg detective named Jake Bullet (whose duties are restricted to traffic control). Rimmer learns he is really a putrid wino named Billy Doyle, while Lister is his billionaire half-brother, Sebastian.

Having discovered the world is run by a totalitarian regime, the players are apprehended by an armed government agent, who recognises Sebastian as the head of a national extermination initiative known as the Ministry of Alteration. The agent tries to shoot an innocent little girl, but Jake kills him first.

As the companions escape in Sebastian's limousine it becomes apparent that this nightmare scenario is actually a hallucination, and everyone is acting out their delusions on the deck of Starbug. Lister, Rimmer, Kryten and Cat all attempt to commit suicide in a fit of despair, but Holly, Starbug's computer, manages to talk them down as the mood-stabilizing drugs take effect and everyone returns to normal.