The Earth colony Terra Alpha, the future. With the aid of her sweet-natured executioner, Helen A, ruler of the planet, has ensured the population is happy - on pain of death! The Doctor and Ace decide to fight for the right to be miserable.
| Name | Type | Role | |
|---|---|---|---|
| Graeme Curry | Writer | ||
| Ronald Fraser | Guest Star | ||
| Tim Barker | Guest Star | ||
| Sheila Hancock | Guest Star | ||
| David John Pope | Guest Star | ||
| Jonathon Burn | Guest Star | ||
| Harold Innocent | Guest Star | ||
| Richard D Sharp | Guest Star | ||
| Georgina Hale | Guest Star | ||
| Rachel Bell | Guest Star | ||
| Mary Healey | Guest Star | ||
| Chris Clough | Director |