Prisoners of the maniacal Graff Vynda K, the Doctor and Romana must break out and pursue the first segment – even as Unstoff takes it into the most dangerous place on Ribos.
| Name | Type | Role | |
|---|---|---|---|
| Robert Holmes | Writer | ||
| Iain Cuthbertson | Guest Star | ||
| Anne Tirard | Guest Star | ||
| Nigel Plaskitt | Guest Star | ||
| Paul Seed | Guest Star | ||
| Robert Keegan | Guest Star | ||
| Timothy Bateson | Guest Star | ||
| George Spenton-Foster | Director |