When the Second Doctor, Polly, Ben and Jamie visit a human colony that appears to be one big holiday camp, they think they have come across a truly happy place. Yet a shadowy presence soon makes them realise that the surface contentment is carefully controlled.
| Actor | Role |
|---|---|
 Patrick TroughtonThe Doctor | The Doctor |
 Anneke WillsPolly | Polly |
 Michael CrazeBen Jackson | Ben Jackson |
 Frazer HinesJamie McCrimmon | Jamie McCrimmon |
 Peter JeffreyPilot | Pilot |
| GGraham ArmitageBarney | Barney |
| IIan FairbairnQuesta | Questa |
| JJane EnshaweSunaa | Sunaa |
| SSandra BryantChicki | Chicki |
| KKarol KeyesChicki | Chicki |
| MMaureen LaneDrum Majorette | Drum Majorette |
| TTerence LodgeMedok | Medok |
 Gertan KlauberOla | Ola |
| GGraham LeamanController | Controller |
| AAnthony GardnerAlvis | Alvis |
| DDenis GoacherControl Voice | Control Voice |
| RRichard BealeBroadcast/Propaganda Voice | Broadcast/Propaganda Voice |
| RRobert JewellMedia Operator | Media Operator |
 John HarveyOfficia | Officia |
| JJohn CaesarGuard | Guard |
| SSteve EmersonGuard | Guard |
| DDanny RaeGuard | Guard |
| RRalph CarriganCheerleader | Cheerleader |
| RRoger JeromeCheerleader | Cheerleader |
| TTerry WrightCheerleader | Cheerleader |