In 2015 London, Lucie encounters the Eightfold Truth, a fringe group claiming a rebel sun is coming to purge Earth. The Doctor soon discovers the threat is real.
| Name | Type | Role | |
|---|---|---|---|
| Barnaby Edwards | Guest Star | Newsreader | |
| Sophie Winkleman | Guest Star | Kelly Westwood | |
| Stephen Moore | Guest Star | Clark Goodman | |
| Katarina Olsson | Guest Star | The Headhunter | |
| Sanjeev Bhaskar | Guest Star | Dr Avishka Sangakkara | |
| Richard Earl | Guest Star | Rob | |
| Anthony Spargo | Guest Star | David | |
| Beth Chalmers | Guest Star | Queen |