The TARDIS has arrived on a far-distant and seemingly idyllic world. Yet the Doctor, Steven and Dodo learn it hides a terrible secret: the apparently civilised Elders maintain their advanced society by draining and transferring to themselves the life-force of the defenceless Savages.
| Actor | Role |
|---|---|
 William HartnellThe Doctor | The Doctor |
 Peter PurvesSteven Taylor | Steven Taylor |
 Jackie LaneDodo Chaplet | Dodo Chaplet |
 Frederick JaegerJano | Jano |
 Ewen SolonChal | Chal |
| GGeoffrey FrederickExorse | Exorse |
| NNorman HenrySenta | Senta |
 Patrick GodfreyTor | Tor |
| PPeter ThomasCaptain Edal | Captain Edal |