This episode opens with a flashback to the Aigburth Arms pub, in Liverpool, 2155, where we see a man named Frank discovering a baby in a box under the pool table.
On the box is written "OUROB OROS": the barmaid deplores the fact that his unknown parents could not even decide what name to give him (or how to spell it), interpreting the writing as a misspelling of "our Rob or Ross".
He explains to our Lister that in their reality, Kochanski (Chloë Annett) found out that he had smuggled Frankenstein on board ship and took the cat away from him.
As they load aboard some supplies from Kochanski's ship, Lister sees a crate with a strange symbol and asks about it.
Lister realises that the box he was found in didn't say "our Rob or Ross" but "Ouroboros" and suddenly works out the mystery behind his abandonment.
Knowing his whole existence depends on saving Kochanski, Lister uses a crossbow and some rope taken from her own ship's supplies and does exactly that... but in so doing shoots the harpoon into her leg, causing her to make an obscenity-laden phone call to him.
In the medibay later, Kochanski becomes determined to find some way back to her crew but a devastated Kryten tells her the dimension gateway is closed for good.
Eighteen months later, Lister uses the time drive to send himself and his baby son back to the Aigburth Arms in 2155.
After bidding his child goodbye, Lister puts him under the pool table in a box marked 'Ouroboros' and leaves seconds before Frank walks in...
[citation needed] The Aigburth Arms (where the opening scene takes place) is named after a real Liverpool pub which Rob Grant and Doug Naylor used to frequent.
"[4] However, DVDActive called Ouroborus "the weakest episode" of the series, and noted that Kryten's more neurotic personality traits were "initially interesting [but] the sight of a blubbing robot gets very irritating very quickly.
"[5] Sci-Fi Online liked the episode, and thought that it "contains a great central concept and impressive model and CGI effects.