The Sea Devils

The Doctor and Jo visit the Master in his island prison. Besides visiting his old friend the Doctor is after assurance that the Master is secure - that he hasn't managed to use his hypnotism to escape. Colonel Trenchard gives the Doctor the impression that the guards are impervious to hypnotism.

Colonel Trenchard lets slip that ships have been disappearing, and the Doctor decides to have a look. After triangulating three of the disappearances the Doctor finds an abandoned base, and starts his investigations there - and Jo tags along. Whilst there they are attacked by Sea Devils, related to the Silurians.

The Doctor manages to escape and notifies the Navy, who want to launch an attack. The Master is involved, with Colonel Trenchard assisting. The Doctor stalls the Navy by offering to negotiate, but with the Master present this is difficult. The Doctor pretends to help the Master construct a machine that will enable the Sea Devils to emerge victorious, but instead sabotages it, and the Doctor and the Master escape as the Sea Devils' base is destroyed.

The Master fakes illness. He hypnotises, and disguises, one of the rescue crew, and manages to escape from the authorities.

• The Master: Roger Delgado;
• Captain John Hart: Edwin Richfield;
• Third Officer Jane Blythe: Jane Murphy;
• Colonel George Trenchard: Clive Morton (1-4);
• Sea Devil: Pat Gorman (1-2,4-6);
• LDG Telegraphist Bowman: Alec Wallis (1,4-6);
• Castle Guard Barclay: Terry Walsh (1-3 - uncredited for 2);
• Alan Clark: Declan Mulholland (1-2);
• Radio Operator: Neil Seiler (1);
• Edwin Hickman: Hugh Futcher (1);
• Robbins: Royston Tickner (1);
• Castle Guard Wilson: Brian Justice (1);
• CPO Smedley: Eric Mason (2);
• Lieutenant Commander Tony Mitchell: David Griffin (3-5);
• Commander Ridgeway: Donald Sumpter (3-5);
• LDG Seaman Lovell: Christopher Wray (3-5);
• Castle Guard Drew: Stanley McGeagh (2-4);
• CPO Summers: Colin Bell (4-5);
• Lieutenant Commander Watts: Brian Vaughn (4);
• Chief Sea Devil: Peter Forbes-Robertson (5-6);
• Walker: Martin Boddey (5-6);
• A/B Girton: Rex Rowland (5);
• Rear Admiral: Norman Atkyns (5);
• CPO Myers: John Caeser (6);


• UNCREDITED CAST:
• Voice of DJ: Michael Briant (2);
• Sea Devils: Steven Ismay, Brian Nolan, Frank Seton, Jeff Witherick;
• Chateau Guards: Stewart Barry, Bob Blaine, Les Clark, Jim Dowdall, Brian Gilmar, Phillip Weston;
• Ratings: Jim Dowdall, Nick Llewellyn, Roy Pearce, Dennis Plenty, Ron Tingley;
• Naval Base Sailors: Jim Dowdall, Brian Gilmar, Nick Llewellyn, Roy Pearce, Dennis Plenty, Ron Tingley, Phillip Weston; Stuntmen: Marc Boyle, Peter Brace, Alan Chuntz, Jack Cooper, Stuart Fell, Billy Horrigan, Mike Horsborough, Mike Stephens, Terry Walsh, Derek Ware;