Deep space, 5000AD. An Earth supply shuttle is infected by a strange sentient space-borne virus, which quickly spreads to the crew of the refuelling station on the moon Titan. Even worse, the Doctor himself falls victim. But why is Leela immune, and what is the virus's ultimate goal?
| Name | Type | Role | |
|---|---|---|---|
| Bob Baker, Dave Martin | Writer | ||
| Anthony Rowlands | Guest Star | ||
| Edmund Pegge | Guest Star | ||
| Jay Neill | Guest Star | ||
| Derrick Goodwin | Director |