While the Master, victim of his own attempt to improve his TCE weapon, seeks restoration through Sarn's numismaton gas, the truth of Turlough's past comes out at last, though to guarantee the safety of his brother and the Sarn people, Turlough must consider a great personal sacrifice.
| Name | Type | Role | |
|---|---|---|---|
| Peter Grimwade | Writer | ||
| Jonathon Caplan | Guest Star | ||
| Barbara Shelley | Guest Star | ||
| Max Arthur | Guest Star | ||
| James Bate | Guest Star | ||
| Simon Sutton | Guest Star | ||
| Dallas Adams | Guest Star | ||
| Edward Highmore | Guest Star | ||
| Peter Wyngarde | Guest Star | ||
| Fiona Cumming | Director |