Under Rimmer’s supervision, Kryten takes a driving lesson at the wheel of Starbug, Red Dwarf’s newly-revealed scout ship. A chance meeting with a wormhole, however, sends student and teacher to a world that literally has everything backwards. Conversations end at the beginning, fights un-blacken eyes, and beer tastes best when vomited into the glass. By the time Lister and the Cat mount a rescue, their crewmates have discovered the bizarre upside of life in reverse motion.

Holly’s discovery of “five black holes” in Red Dwarf’s path prompts the crew to abandon ship, Rimmer and Lister crashing on a nearby ice planet when Starbug collides with a meteorite. With hope fading as the days pass, the marooned pair must sacrifice more than just their rivalry to survive, Lister’s diet reduced to dog food and the only thing he hates more: Pot Noodles. The need for firewood, meanwhile, soon imperils their most prized possessions: Rimmer’s camphor wood trunk and Lister’s guitar.

An uninvited alien guest brings the worst out of the crew – then eats it. Feeding on the fear, anger, guilt and vanity of its prey, the shape-shifting “Polymorph” creates an even more dysfunctional adversary: their alter-egos. Unable to hatch a plan that doesn’t involve leaflet campaigns and kicks to the balls, the psychotic Lister, placard-waving Rimmer, boorish Kryten and drunken Cat must unite in order to survive, the face of the enemy changing at every turn.

Lister asks a malfunctioning dispenser unit for a Toffee Crisp and triggers the ship’s self-destruct sequence, the only way out being a “body swap” with a dead, high-ranking officer. Inspired, Rimmer suggests a two-week trade: Lister’s body for his, the sweetener being that he’ll return it in tip-top physical condition. Unfortunately, the pleasures of the flesh prove too much for the weak-willed hologram, the fitness regime descending into an orgy of binging and self-abuse.

Lister’s despair at life after humanity lifts when Kryten, having discovered some mutated development fluid, creates photographs that literally revisit the past. With no regard for the laws of causality, Lister looks to exploit the discovery for his own ends, talking his teenaged self into inventing the “Tension Sheet”, a billion-selling sheet of painted bubble-wrap. Suddenly alone on Red Dwarf, Rimmer is left with little choice but to “save” his crewmate from a life of luxury.

The crew intercepts a message from Kryten’s manufacturer, DivaDroid International, declaring him obsolete and announcing his successor, the all-singing, all-dancing Hudzen-10. Left with days to live by an inbuilt self-destruct programme, Kryten reflects on his robot existence, taking solace in the thought of an electronic afterlife. A farewell party prompts a change of heart, however, jeopardised by the arrival of his super-strong, murderously deranged replacement.