The Time Lords send the Doctor and Jo on a mission to deliver a sealed message pod to an unknown party aboard a Skybase orbiting the planet Solos in the 30th century. They are caught quickly in a power struggle between the cruel Marshal of Solos and the young Solonian Ky over the future of Solos - a future that hinges on the contents of the message.
Jon Pertwee
as The Doctor
Katy Manning
as Jo Grant
Paul Whitsun-Jones
as Marshal
James Mellor
as Varan
Garrick Hagon
as Ky
Christopher Coll
as Stubbs
George Pravda
as Jaeger
John Hollis
as Sondergaard
Rick James
as Cotton
John Scott Martin
as Mutt
Geoffrey Palmer
as Administrator
