On the planet Alzarius in the alternate universe of E-Space, the Doctor, Romana and K9 find survivors of a crashed starliner, strange creatures lurking in the marshes and a genetic riddle which stretches back centuries.
| Directing | Peter Grimwade | Director |
| Writing | Andrew Smith | Writer |
| Sound | Paddy Kingsland | Original Music Composer |
| Production | Barry Letts | Executive Producer |
| Production | John Nathan-Turner | Producer |
| Writing | Christopher H. Bidmead | Script Editor |
| Costume & Make-Up | Amy Roberts | Costume Design |
| Art | Janet Budden | Production Design |
| Camera | Max Samett | Camera Operator |
| Editing | Mike Houghton | Editor |
| Sound | Mervyn Broadway | Sound |
| Costume & Make-Up | Frances Needham | Makeup Artist |
| Production | Susan Box | Production Assistant |
| Camera | Alan Kerridge | Camera Operator |
| Camera | Reg Poulter | Camera Operator |
| Crew | Dick Mills | Special Sound Effects |
| Lighting | Mike Jefferies | Lighting Director |
| Sound | John Holmes | Sound |
| Editing | Rod Waldron | Editor |
| Visual Effects | AJ Mitchell | Visual Effects |
| Visual Effects | John Brace | Visual Effects Designer |
