The Book: Peter Jones Zaphod Beeblebrox: Mark Wing-Davey Roosta: Alan Ford Frogstar Prisoner Relations Officer/Eddie the Computer: David Tate Arthur Dent: Simon Jones Ford Prefect: Geoffrey McGivern Gargravarr: Valentine Dyall Announcer (uncredited): John Marsh
The episode opens with Zaphod and Roosta in the Guide building, which is being towed to the Frogstar, "the most totally evil place in the Galaxy". Roosta explains that they are going to feed Zaphod to the "Total Perspective Vortex", which no one has ever survived. A Frogstar Prisoner Relations Officer teleports in, to taunt Zaphod.
Meanwhile, in Earth's past, Ford and Arthur are still dealing with the rescue ship that has half-appeared in front of them. Rather stuck for how to signal it, they wave a towel at it, and surprisingly, the spaceship appears to notice this and lands rather catastrophically, trapping them under a boulder, and sending the towel into a lava flow.
They appear to be stuck, so they ask The Guide what to do if one is stuck under a rock, with no hope of rescue. The guide has an entry that begins, 'Consider how lucky you are that life has been good to you so far...'
However, it becomes apparent that the boulder they are under is actually the ship, the Heart of Gold, and Zaphod Beeblebrox comes out of it, rather the worse for wear. He explains that he has been put in the Total Perspective Vortex, and survived. After this, he celebrated and is hungover from a week's celebration. He explains that the towel had been fossilised, and when the Earth was blown up two million years later, the Improbability Drive picked it up.
The story then continues in flashback, picking up with Zaphod and Roosta on the Guide building. They attempt to escape with a "body debit" (teleport) card, but are foiled by the Relations Officer. He then tricks Zaphod into signing a consent form for entering the Vortex, and is then teleported to the service. He meets Gargravarr, a disembodied voice, the guardian of the Vortex. He is then placed in it, and exposed to its action, which is to place the user into Total Perspective by showing, with unfiltered perception, themselves into relation to the universe, for a moment. Zaphod survives, much to the astonishment of Gargravarr. He reports that it showed him that he is a "really great guy". The episode ends here.