The Sea Devils attack the island prison and rescue the Master, prompting the Doctor to venture underwater to try and contact them.

Starring:

Elisabeth Sladen, Frazer Hines, Jacqueline Hill, John Levene, John Scott Martin, Jon Pertwee, Katy Manning, Nicholas Courtney, Pat Gorman, Patrick Troughton, Peter Davison, Tom Baker, William Hartnell, William Russell

Genre:

Adventure, Drama, Sci-Fi