The crew travels to the planet Albian in search of information on the location of the Federation computer system Star One. Avon defuses a bomb with the help of Del Grant, who had thought Avon deserted his sister.
| Name | Type | Role | |
|---|---|---|---|
| Terry Nation | Writer | ||
| Geoffrey Snell | Guest Star | ||
| Tom Chadbon | Guest Star | ||
| Sidney Kean | Guest Star | ||
| James Kerry | Guest Star | ||
| Lindy Alexander | Guest Star | ||
| Nigel Gregory | Guest Star | ||
| Robert Arnold | Guest Star | ||
| Paul Shelley | Guest Star | ||
| Vere Lorrimer | Director |