The Governor forces the Doctor to tell him the true value of zeiton-7 but Sil attempts to derail his plans by subjecting Peri and Areta to an enforced mutation.
| Name | Type | Role | |
|---|---|---|---|
| Phillip Martin | Writer | ||
| Owen Teale | Guest Star | ||
| Forbes Collins | Guest Star | ||
| Graham Cull | Guest Star | ||
| Sheila Reid | Guest Star | ||
| Nicolas Chagrin | Guest Star | ||
| Geraldine Alexander | Guest Star | ||
| Hugh Martin | Guest Star | ||
| Jason Connery | Guest Star | ||
| Ron Jones | Director |