An unnamed world, an unknown time. A vast mining vessel trawls a sea of mineral sand for valuable ores, the tiny human crew served by an army of humanoid robots. But as the Doctor and Leela arrive, one of the crew is found murdered... and if they didn't do it, who did?
Elenco:
William Hartnell
,
Patrick Troughton
,
Jon Pertwee
,
Tom Baker
,
Peter Davison
,
Colin Baker
,
Sylvester McCoy
.