Written by Malcolm Hulke
"This is our planet. My people ruled the Earth when man was only an ape"
| Episode Title | Premiere Date |
| Episode 1 | 26/02/1972 |
| Episode 2 | 04/03/1972 |
| Episode 3 | 11/03/1972 |
| Episode 4 | 18/03/1972 |
| Episode 5 | 25/03/1972 |
| Episode 6 | 01/04/1972 |
Arrested after the events at Devil's End, the Master has been incarcerated at a top-security prison on a remote island off the south coast of England. When the Doctor and Jo Grant pay a visit to their old enemy, they find him a reformed character. But can the spate of mysterious shipping accidents and garbled reports of sea monsters in the local area really be a coincidence? The Doctor soon finds himself pitted against the Sea Devils, an ancient race of reptiles intent on eliminating Mankind and reclaiming the Earth for themselves...
Cast & Crew
The Doctor: Jon Pertwee
Jo Grant: Katy Manning
The Master: Roger Delgado
Captain Hart: Edwin Richfield
Trenchard: Clive Morton
Commander Ridgeway: Donald Sumpter
Chief Sea Devil: Peter Forbes-Robertson
Producer: Barry Letts
Director: Michael Briant
Scriptwriter: Malcolm Hulke
