The Book: Peter Jones Arthur Dent: Simon Jones Ford Prefect and Varntvar The Priest: Geoffrey McGivern Zaphod Beeblebrox: Mark Wing-Davey Lintillas and Android Stewardess: Rula Lenska The Allitnils: David Tate Poodoo: Ken Campbell Autopilot and Zarniwoop: Jonathan Pryce Marvin the Paranoid Android and The Man in the Shack: Stephen Moore Announcer (uncredited): John Marsh
The episode begins with a reprise of the action from Fit the Eleventh: Ford and Zaphod have discovered a derelict spaceport, including one ship, still intact, with its supply lines still connected, and still having power. Zaphod creates a stethoscope for both heads out of some pieces of tubing, and is shocked at what he hears inside. Ford asks to listen, and finally, everyone gets to hear an android stewardess making an announcement about their delayed space flight. Zaphod calculates that the ship is in fact over 900 years late. Ford and Zaphod agree to find their way into the ship to investigate further.
Meanwhile, Arthur and Lintilla finally find Lintilla's two clones on Brontitall, but they, along with Marvin, are discovered by the Footwarriors as power is restored. Arthur agrees to run down the corridor while the others lay down cover fire with "a gun of some sort", then Arthur will have them throw the gun to him, so that he can lay down cover fire while they run to meet him. As Arthur completes the first part of this task, he's met by a man named Poodoo, a priest named Varntvar, and three men named Allitnil. During this confusion, Arthur manages to get Lintilla to throw the gun down the corridor, and starts firing to cover their run to join him. While Arthur does this, Poodoo is explaining how keen he is to introduce the Allitnils to the Lintillas, for a quiet social evening, and "a priest [is] on hand in case anybody wants to get married at all. Just to round off the evening." Arthur questions his sanity.
The Lintillas finally join Arthur, and Poodoo seizes his opportunity to introduce the Allitnils to them. They are immediately overwhelmingly attracted to each other, but are warned off from kissing each other until married. The priest is then called upon to perform three weddings. As the weddings conclude and the men kiss their brides, two of the three pairs disappear in "a puff of unsmoke" as Arthur discovers that the marriage certificates are actually cloning machine company "Agreements to Cease to Be" and cries out, stopping the final couple from kissing.
At this point, we go back to Ford and Zaphod entering the very late space ship, just as the passengers are being woken from suspended animation for coffee and biscuits. Ford and Zaphod flee the scene, eventually arriving on the flight deck, where they are continually ordered by the autopilot to return to their seats. The autopilot argues with them over the statistical likelihood of another civilisation delivering the lemon soaked paper napkins required by the spaceship before it can depart, and Ford and Zaphod flee again, this time to the First Class compartment. Here, a man introduces himself to Zaphod as Zarniwoop, whom Zaphod had been seeking since Fit the Seventh.
The action returns to Arthur, the remaining Lintilla, and Marvin. We learn that Arthur had killed the last Allitnil, the anti-clone, and Marvin tied up Poodoo and Varntvar, leaving them forced to listen to a cassette tape of Marvin's autobiography. As they finally exit the Dolmansaxlil building, they set out for the same spaceport that Ford and Zaphod are in, but then discover that the suspended cup is heading towards the surface, with the Heart of Gold still inside.
Meanwhile, Zarniwoop has offered Ford and Zaphod some drinks, and attempts to explain the whole situation to them. Zarniwoop starts by explaining that they had been in an artificiall