|Edition: || UK (VHS)|
|When: ||April 1995|
|Format: ||1 x VHS PAL|
The Doctor, Romana and K9 continue their search for the six disguised segments that make up the powerful Key to Time.
The TARDIS lands on the world of Zanak, despite the Tracer indicating that they seek another planet altogether — Calufrax. On Zanak they find the populace living under the cruel tyranny of the Captain; a bullying, arrogant cyborg who is using the hollow planet as a giant spaceship materialising it around worlds and then mining them dry.
Living apart from the other people of Zanak are the Mentiads, a feared group of silent men with heightened extra-sensory powers. The Doctor tries to rally the Mentiads into attacking the Captain's base and free the planet from his control. But the Doctor has failed to realise who actually wields the power on Zanak...
Having failed to find the second segment, Romana finds herself put to work on the planet's massive engines, K9 battles the lethal robot parrot Polyphase Avatron and the Doctor discovers the identity of the next planet targeted for destruction... Earth!
Transmission date: 30th September 1978 to 21st October 1978