The story in each show was that the two celebrity contestants and a member of the public had travelled by space ship to the planet Arg. Their overall task varied with each series. For example, the team might be charged with finding a crystal needed to power their ship to return to Earth. The programme is often considered to have been a forerunner of The Crystal Maze.
Arg was inhabited by shapeshifting dragons known as Argonds. As a reference to this, most proper nouns in the programme, including Argond, were anagrams of the word dragon. All Argonds shifted shape within the first few minutes before the contestants arrived, most to human form to avoid scaring them.
The contestants had to complete a number of tasks in order to achieve their overall goal (e.g. regain their crystal and return to their ship). Many tasks involved the drogna, a small transparent plastic disc containing a solid geometric figure, which was the currency of Arg. The value of a drogna was its numbered position in the visible spectrum multiplied by the number of sides of the figure. For example, a red circle is worth one unit, an orange circle is worth two units, a red triangle and a yellow circle are both worth three, and so on.