Format: Paperback

Publisher: Target Book 1979

Pages: 144

Reluctantly cancelling his well-earned holiday, the Doctor sets off in the TARDIS to trace and reassemble the six segments of the Key to Time on which the stability of the entire Universe depends.

Assisted by the argumentative Romanadvoratrelundar and K9, he lands on the planet Ribos in search of the first segment and finds himself entangled in the machinations of two sinister strangers, Garron and the Graff Vynda Ka.