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 | ||
| James Bate | Guest Star | ||
| Jonathon Caplan | Guest Star | ||
| Dallas Adams | Guest Star | ||
| John Alkin | Guest Star | ||
| Edward Highmore | Guest Star | ||
| Peter Wyngarde | Guest Star | ||
| Barbara Shelley | Guest Star | ||
| Fiona Cumming | Director |