In 2155, a patron of the Aigburth Arms is amazed to find a baby under the pool table, inside a box with "Ouroboros" written on it. Taking the box and baby to the barmaid, they read the word as a mangled attempt at naming the baby 'Our Rob or Ross', as the barmaid wonders what will become of him...
That boy grows up to be Dave Lister. Three million years later aboard Starbug, Lister is gifted a pink dressing gown and fuzzy slippers by Kryten who intends to alter them for Lister who then gets some dental floss gets stuck in Lister's mouth thanks to him using wood glue to fix his tooth cap. At that point, the the Cat detects an oncoming anomaly. Heading to the cockpit, the three find that it is a dimensional tear between realities and decide that flying Starbug straight into it is better than what would be a failed attempt to outrun it. Heading in, the crew find that a dimensional bridge has formed in cargo bay.
When the Dwarfers walk down the tunnel, they encounter their counterparts from a parallel universe. In that reality, the other Lister is a hard-light hologram and explains by means of a flashback to the pre-accident Red Dwarf it was his ex-girlfriend Kristine Kochanski who was caught with the smuggled cat and survived the accident due to being put in stasis instead of Lister. The two are now being in a loving relationship thanks to Lister developing a caring and sensitive side as a result of years being a soft-light hologram.
Lister is astonished to see Kochanski alive and tries to impress her (difficult since he is still wearing the gown, slippers and dental floss). A Kinitawowi battle cruiser interrupts the meeting, penetrating non-space and firing at the linkway tunnel, breaking it. Kochanski falls into non-space, but Lister manages to haul her back up using the dental floss hanging from his teeth and the Dwarfers take her back to their own Starbug.
When Kochanski wakes, she is annoyed at being on a ship filled with crude and uncultured versions of her own crew, especially when Lister allows her to think he is her version to get a kiss from her. At that point, the GELF cruiser starts attacking Starbug, with Lister's GELF wife (from the episode Emohawk) aboard looking to get her husband back. Kochanski, a brilliant navigation officer, helps the crew trick the GELFs into crashing, then becomes determined to re-establish the dimensional linkway. Kryten begins to get jealous of the effect that she has on Lister, while both Lister and The Cat do all they can to impress her. Eventually, Kochanski repairs the linkway and heads back to her own dimension.
Lister gives her a sperm sample so that she can have a child, and the two later bid each other goodbye. As the crew then start sorting out the supplies they got from Kochanski's ship, Lister gets curious about a symbol showing a snake eating its tail. Kryten explains the snake represents infinity and by biting its own tail it creates an everlasting circle with no beginning or end. The reason its on the box is that it used to contain ever-lasting 'Ouroboros' batteries (Ouroboros being the name of the symbol). Lister, in shock, realises that was the message on the side of the box he was found in and not 'Our Rob or Ross', and suddenly works out the mystery behind his abandonment... the embryo in the in-vitro tube is himself and he is his own father while Kochanski is his mother, and after the baby is born they'll have to go back in time to the Aigburth Arms to leave him under the pool table. Writing Ouroboros on the box was their way of explaining. He realises he needs to get the test tube back and rushes down the linkway to stop Kochanski, but the GELFs return and sever the tunnel. Kochanski decides to jump the gap between dimensions, but misses her target and falls into non-space. Lister manages to fire a crossbow bolt with a line attached down to her, unfortunately skewering her leg in the process. After subjecting Lister to a variety of obscene language, she reluctantly joins their crew but vows to find another linkway.
Months later, Lister uses the time drive to place his infant self underneath the pool table, explaining that he isn't being abandoned like he'll think he was for years, but is being left there to create an unbreakable paradox. As a result, the Human species can never become extinct. Lister then leaves the baby and uses the time drive to return to the future just as the patron who discovers him is about to enter the pub, thus completing the circle.
A number of dialogue scenes had to be severely shortened for "Ouroboros" to fit the allocated BBC time slot - and when the cut couldn't get any tighter, rather than lose 40 seconds more of an already fast-paced episode the team elected to remove the opening titles.
These, along with many of the lost character exchanges, were reinstated for the "Xtended edition" available for viewing on the Series VII DVD. The edition fixes at least one glitchy piece of continuity. In the Cat's first moments with Kochanski, he coins the term 'Officer Bud Babe', but when those early lines hit the cutting room floor, some viewers were left baffled when he referred to Krissie as 'Officer BB' for the duration of the series, even though the Cat does go on to use the full term in a later scene in the same episode, but only after the term "Officer BB' is used first.
As available for viewing on the Series VII DVD. The trimmed dialogue is reincorporated for the "Xtended version" of the episode:
- When Lister sneezes out his tooth cap, he blames Kryten's sticky toffee pudding, which he says is just too sticky.
- As the Cat see's Lister's 'new outfit' for the first time, he says "I thought you had less style than a 1970s TV cop."
- An extended dialogue between Lister and Rimmer in the flashback sequence to Red Dwarf before the accident. Lister is arriving on Red Dwarf from shore-leave on Mimas on a late shuttle; Rimmer is waiting in the arrivals area holding a sign that says "smeghead". As Rimmer says that he's reported him as A.W.O.L, Lister says "S.O.W.H.A.T."
- As Kochanski asks Lister if he is the kind of guy who would take advantage of a girl who is half insensible, she corrects herself saying that actually they must be his "favourite kind".
- The Cat and Kryten mock Lister on his earlier, very reluctant marriage to a hairy GELF bride. Cat says thew wedding was beautiful, it broke his heart when they separated, and Kryten says that "it was such a good match".
- Extended Kryten saying Kinitawowi names. After he says the long and ridiculous name of the GELF Chief Justice, Kochanski says "let's call him 'ach-ach-ach' for short".
- A significant portion of the crew inside the Starbug cockpit as they evade the Kinitawowi battle cruiser. After navigation officer Kochanski explains to the Cat the meaning of "coordinates", he says "I knew that... What was that first number again?" Kochanski replies that she's seen "fairground darts that are sharper than you guys". Lister responds with "Kris, will you stop treating us like we're a useless bunch of no-hopers? We know what we're doing, okay?" Kochanski then asks what has happened to their Red Dwarf (they have lost it, later revealed to be stolen by the nanobots) and the others are reluctant to tell her that they have lost Red Dwarf. They all look at each other awkwardly, and Kryten says that it's a "long, long, long, long" story.
- This is the first episode to not feature Arnold Rimmer as one of the crew and a main character, since he left to become Ace Rimmer in the previous episode. Rimmer does however appear in one scene in Ouroboros; Lister's flashback an earlier time on Red Dwarf. Rimmer would appear in flashbacks, virtual reality simulations and dreams through the rest of Series VII. In Series VIII Rimmer would be resurrected in the flesh by the nanobots.
- The inclusion of Kochanski was necessary to balance out the cast with the departure of Rimmer. Before deciding on bringing back Kochanski, Doug Naylor first considered bringing back Captain Hollister, and his second choice was Lister's old best friend Olaf Petersen, which Naylor said he was keen to do most. Mindful of the possible movie however, Naylor chose to bring back Kochanski since it would provide the cast with an attractive female.
- Lister uncovers the truth of his birth and parents in this episode. He had previously mentioned that as a baby he was found under a pool table in a box in the episodes The Last Day, Dad, and Out of Time. The consequences of Lister being his own father are later explored in the Series X episode Fathers & Suns.
- The "Aigburth Arms" is a real pub in Liverpool that the writers Rob Grant and Doug Naylor used to frequent. It is now called "The Victoria".
- This episode acts as a partial-sequel to Emohawk: Polymorph II due to the reappearance of Lister's Gelf wife. There is also a reference to one of their "warmest greetings" as among the supplies traded between the Red Dwarf crew and their counterparts is a crossbow, which Kryten mentioned that he "thought it would come in handy next time you (Lister) ran into your wife".
- The parallel universe hologram Lister's three million year old flashback was the first time the pre-accident Red Dwarf had been seen since the Series II episode Stasis Leak.
- The flashback to Red Dwarf also briefly shows the stern of the shuttlecraft White Midget, the only time White Midget has been seen in the television series outside of the novels. This is the ship which returns Lister to Red Dwarf from shore-leave on Mimas.
- The same flashback also shows Lister with the items he acquired on shore-leave Mimas (Miranda in the novels); the gaudy trinkets and blingy junk he is pushing in a shopping trolley. Although not seen, these new possessions would have included his robot fish, Talkie Toaster and a hidden, smuggled pet cat. All these items were said to be acquired on the same trip, and which is confirmed in the novels.
- This is the only episode to reference the novels. Lister mentions that Kryten accidentally killed the crew of the Nova 5. Although the exact circumstances are not mentioned, this ties in to Infinity Welcomes Careful Drivers in which Kryten causes the crash of the ship by pouring soapy water into the navigation computer in a misguided attempt to clean it. Additionally, Kochanski dumping Lister, prompting him to take a trip where he found Frankenstein was also previously described in Infinity Welcomes Careful Drivers.
- The episode ran long and as a result was the first of two consecutive episodes to air without opening credits. When an extended version was created for later DVD release, the credits were put back on, however the "filmizing" process applied to the episode was not applied to the credits, providing a brief glimpse of how Series VII looked in its original shot-on-video form.
- With Clare Grogan unavailable to return as Kochanski, the part went to Chloe Annett who had previously auditioned for a role in the The Ten Percenters, another project of Grant Naylor Productions.
- FX guy Mike Tucker created the flashback shot of White Midget approaching Red Dwarf using a redressed Blue Midget, stock footage with cut-outs of Red Dwarf, background lighting, Vaseline and mirrors.
- The Aigburth Arms set was a re-dressing of Laser Quest at Kingston.
- Baby Lister is played by Danny John-Jules's nephew. According to DVD commentary, John-Jules volunteered his nephew when he discovered the baby originally recruited to play young Lister was too dark-skinned to be convincing as a younger Craig Charles.
- Kochanski: Rimmer?
Rimmer: Yes, ma'am?
Kochanski: Have sex with someone, and that's an order.
Rimmer: Yes, ma'am. Right away, ma'am.
Lister: [Hands him a card] Here, phone this number. Say I sent ya. Tell her it's an emergency.
- Kryten: We've lost sight of Miss Kochanski's ship, sir. And we're fast running out of time.
Lister: Yeah, it's good, isn't it?
Kryten: No sir, I don't believe it is.
Lister: Why? Don't you like her?
Kryten: I'm a mere mechanoid, sir. It's hardly my place to point out what a bossy old trollop she is.
- Kryten: I'm going to end up on my own again, just like I did on the Nova 5.
Lister: You killed the crew, Kryten! No wonder you were left on your own! All right, it was an accident, but nonetheless!
Kryten: But what about before that? It was the same on the SS Augustus!
Lister: Well, they died of old age!
Kryten: You see?
- Kryten: You're not good enough for him. That's all. OK, he may walk around smelling like a Balti House laundry basket, but he doesn't need the likes of you swapping dimensions like there's no tomorrow and bewitching him with your... in and out bits. All pointy and unnecessary.
Kochanski: You've got big problems, you know that?
- Kryten: [Lister impales Kochanski with a harpoon in attempting to rescue her from 'non-space'] It's an obscene phone call, sir. I think it's for you.
- Lister: [To his baby self before leaving him in the Aigburth Arms] For a long time, you'll think that you were abandoned, but you *weren't*, man. You were put here to create a paradox, an unbreakable circle. With us going 'round and 'round in time, the human race can never become extinct. We're like... a kind of 'holding pattern'. I'll see ya, son.