The Doctor's party remains divided and scattered as the immense transport docks at the Terminus space station, which turns out to be a leper colony at the exact centre of the known universe. As they find their way around and investigate, Nyssa shows signs of contracting the disease.
| Name | Type | Role | |
|---|---|---|---|
| Stephen Gallagher | Writer | ||
| Martin Potter | Guest Star | ||
| R.J. Bell | Guest Star | ||
| Martin Mulcaster | Guest Star | ||
| Dominic Guard | Guest Star | ||
| Andrew Burt | Guest Star | ||
| Liza Goddard | Guest Star | ||
| Peter Benson | Guest Star | ||
| Mary Ridge | Director |