Imprisoned inside a complex at the heart of an unstable sun, the Doctor must maintain systems that prevent the deaths of billions — until rebels arrive to free him.
| Name | Type | Role | |
|---|---|---|---|
| Richenda Carey | Guest Star | Gliss | |
| Beth Chalmers | Guest Star | Shill | |
| Anthony Costa | Guest Star | Hagan | |
| Sheridan Smith | Guest Star | Daphne / Chloe |