The ship SS Hermes (which has somehow been reconstructed by the nanites) has been destroyed by a chameleonic microbe, and a lone escape pod with a sole survivor was able to escape, eventually coming across Red Dwarf. As the pod makes it on the ship, the door melts away...
Captain Hollister is sick with Yellow Fever and Rimmer, who's on probation is helping him through it. Rimmer puts forward his wish of becoming an officer but Hollister tells him that he's unlikely to succeed. As he leaves,he oulls the old coin on a string trick on a dispensing machine. The dispensing machine is annoyed at this and becomes Rimmer's enemy.
The other Dwarfers are on probation and Kryten has gotten a present for Kochanski; a new calendar. Kryten is unaware of the concept of a woman's period and had gotten a calendar because he misunderstood Kochanski's comments about it being the wrong time of month. Lister decides to prank Kryten and tells him that the best way to about things is put up a "Have a Fantastic Period" sign in Kochanksi's room and give her a gift-wrapped tampon. Kryten, realising that Lister set him up, decides to get him back by putting Baxter's illegal moonshine in Lister and Rimmer's cell (just as a cell inspection is about to take place). Having nowhere to put the booze, Rimmer and Lister proceed to drink the whole stuff and get really drunk. The duo are sent to medi-bay to get a stomach pump.
Baxter figures out that Rimmer and Lister drank his hooch and threatens the other Dwarfers. Kryten and Kochanski make it to the duo and tell them that they have to escape. Meanwhile, the Cat tries to get beaten up but fails to and has to resort to disguising as a nurse. As the gang make their way to the Starbugs, they find that the chameleonic microbe has gotten on to the ship and inform the rest of the crew, who proceeds to escape from Red Dwarf.
The gang figure out how they can make an antidote. Kochanski figures out that that they could go to a mirror universe to find the antidote. Rimmer heads in and comes across alternate counterparts of our heros; apparently, he's captain, The Cat's smart, Hollister works for Rimmer, and Kochanski's a ditzy secretary. This universe's Cat is able to figure out the antidote and Rimmer makes it back into the Prime Universe..
...to find the Ship in flames, the others having fled, and the Mirror Universe no longer accessible. Rimmer tries to make the antidote but it has reverted to the formula for the virus. Oh, and the dispensing machine decides to attack Rimmer with a can of soda. It all seems hopeless, and Death (literally) comes for Rimmer. Rimmer, in response, knees him in the balls, runs for it and the episode ends there.
Although the episode ends on a Cliffhanger, fans would not see what happened to the Red Dwarf and our heroes for ten years (thanks to a Troubled Production involving the intended movie). The next series of Red Dwarf, (2009's Back To Earth), depicted the ship back to normal again, (minus Kochanski and the majority of the crew and with Rimmer being a hologram again) with the actual explanation of how they got out of this mess (as well as what happened to the rest of the crew) being treated as both an Un-Installment and The Unreveal.
This episode contains examples of:
- Bolivian Army Ending: The episode ends with the ship being eaten by microbes, Rimmer apparently dying but kicking the grim reaper in the balls and running away.
- Brick Joke: Rimmer's interactions with the vending machine.
- Cliffhanger: The episode ends with Rimmer the only remaining crewmember on board a disintegrating Red Dwarf.
- Coin-on-a-String Trick: Rimmer comes to regret using this on a sentient vending machine.
- Did You Just Punch Out Cthulhu?: Did Rimmer actually successfully kick Death in the groin?
- Ditzy Secretary: Kochanski's Mirror counterpart is the Cat's secretary. She's also not too bright, referring to Rimmer's microbe problem as "brainbox-type stuff".
- The End... Or Is It?: "The Smeg It Is!".
- Escape Pod: Talia comes aboard the ship in one.
- Frame-Up: Kryten does this to Lister and Rimmer after getting some very unhelpful "advice" from the former.
- Gargle Blaster: Baxter's illicit hooch. One sip gets Lister and Rimmer plastered.
- Halfway Plot Switch: The first half is about how Lister and Kryten playing pranks on each other turns into a potentially lethal situation... then halfway through they discover that a virus is eating the ship, most of the crew evacuates, and our heroes have to cross into a mirror universe to find the antidote. Although this is set up at the start of the episode, it doesn't come into play until the second half of the episode.
- Hanging Up on the Grim Reaper: Arnold Rimmer knees the Reaper in his groin when he comes to claim him.Rimmer: Not today matey! Only the good die young!
Reaper: That's... never happened before.
- Kids Hate Vegetables: A delete scene has Holly explaining that children love sprouts in the Mirror Universe.
- Mirror Universe: A device is created to allow visits to one. In the end, the entire crew except Rimmer flees to it when the microbe begins destroying Red Dwarf.
- Mistaken for Gay: A deleted scene has Rimmer meet Lister's Mirror Universe counterpart and due to a misunderstanding, thinking he's gay with the alternate Rimmer.
- A Mythology Is True: The Grim Reaper mentions taking Rimmer to the River Styx, implying that Greek Mythology is true in the Red Dwarf universe provided the whole thing wasn't a Dying Dream.
- Oh, Crap!: Lister and Rimmer when they learn their cell is about to be searched and they've got gallons of illegal hooch on site.
- Overly Long Name: The name of the virus is Zogotheniumeliumoxiixiexiphulmifhidikaldrihide, whilst the antidote for the virus is Cesiumfranciolithicmyxialobidiumrixydixydoxidrexidroxhide.
- Standard Snippet: “Adaigo For Strings” plays whilst Rimmer is watching the formula for the virus burn.
- Tempting Fate: Rimmer's comment to the hostile vending machine "And on that day, I will be the Captain of this ship."
- Uncertain Doom: The episode ends with Rimmer kicking the Grim Reaper in the balls and running away and the microbes destroying the ship. As of Back To Earth, Rimmer's a hologram again and the ship is apparently fine with no explanation how the microbes were stopped. Doug Naylor later said in a 2020 interview that the Rimmer in "Back To Earth" is the Rimmer from the first seven seasons returned from being Ace Rimmer, meaning the Season 8 Rimmer must have died as a result of the episode. Well, either that, or he survived, but left the ship for whatever reason.