England, the near future. A strange anti-matter creature arrives on Earth and attacks UNIT HQ. It seems to be specifically seeking the Doctor out - but why? With the Time Lords themselves unable to help, it seems the only person who can help the Doctor is himself - or selves...
| Name | Type | Role | |
|---|---|---|---|
| Bob Baker, Dave Martin | Writer | ||
| Denys Palmer | Guest Star | ||
| Laurie Webb | Guest Star | ||
| Roy Purcell | Guest Star | President of the Council | |
| Patricia Prior | Guest Star | ||
| Clyde Pollitt | Guest Star | ||
| Lennie Mayne | Director |