Elizabeth Estensen and Fred Harris are the first space travellers to visit Arg, along with member of the public Mark Dugdale. Can they collect the crystals needed to return home, when they're being "helped" by the Argonds?
Actress Denise Coffey and Sky at Night presenter Dr. Garry Hunt are joined by Toby Freeman on their trip to Arg. But while Toby was the non-celebrity for the week, he went on to be a games consultant on the series.
Paul Darrow and Lesley Judd's trip to Arg with guest Robert Malos was wiped from the BBC archives. However, a domestic, off-air recording was obtained in order to bring their adventure to the DVD release.