The show was filmed at Pinewood Studios and is notable for the large number of changes in cast and situation that it undertook during its run, despite retaining the same branding throughout.

The show focused on Mercator, an old alien 'Time Baron' with very long eyebrows (played by Roddy Maude-Roxby) who had been banished to Parallel 9 after summoning an earth girl named Calendular as a result of his thirst for knowledge – a criminal offence on his home planet 'Zarb'.

Among the other characters that made regular appearances in the first series were three other criminals who had been banished from their home planet: Steyl, Skyn and Thynkso.

The only connections between this series and the previous run were the name P9, that of Mercator, and the Tope, the clear cubicle which formed a central part of the programme's set, played by Stephen Hope Wynne (who played numerous other characters in all the seasons), and which in this series switched from being a dimensional prison to become the space station's power source.

73; Zee also left, and was replaced by Flynn, played by Kate Lonergan (formerly of Maid Marian and Her Merry Men).