The Silent Enemy

Intro
When Craig, Sharron and Richard visit the fairground, Craig uses his superior skills to throw all his quoits onto the winning peg; he then gives his prize to a pretty girl standing nearby.

Main Story
The entire crew of the submarine 'Keppel' are found dead at their posts. All have died of cardiac arrest. The Champions join a fresh crew to re-trace the voyage but in the Atlantic they lose radio control. They find an uncharted island which is being used for illegal nuclear tests by a country whom the U.N. denied nuclear weapons. The 'Keppel' crew were killed because they came across it. Richard and Craig join a landing party but they are all gassed, except the two Champions, who are taken to be experimented on by mad scientist Minoes. The lads escape but must flee the island before it is engulfed in poison gas.

Guest Cast

 * Rio Fanning as Lighthouse Keeper Two
 * David Blake Kelly as Lighthouse Keeper One
 * Esmond Knight as Minister
 * Marne Maitland as Minoes
 * James Maxwell as Stanton
 * Paul Maxwell as Capt. Baxter
 * Warren Stanhope as Admiral Parker

Uncredited

 * Harry Fielder as Sailor
 * Caron Gardner as Doctor

Episode Crew

 * Casting By Judith Jourd
 * Art Direction By Charles Bishop
 * Makeup Supervisor: Gerry Fletcher -
 * Hair Stylist: Patrick Grant
 * Post-Production Supervisor: Philip Aizlewood
 * Production Manager: Malcolm Christopher
 * Assistant Director: Ken Baker
 * Second Unit Director: John Hough
 * Associate Art Director: John Graysmark
 * Construction Manager: Bill Greene
 * Production Buyer: Sid Palmer
 * Set Dresser: Brian Rider
 * Scenic Artist: A.J. Van Montagu
 * Sound Recordists: Len Abbott and David Bowen
 * Sound Editor: Alan Corder -
 * Special Effects by Sydney Pearson:
 * Camera Operator: Second Unit: James Allen
 * Supervising Electrician: Ted Hallows
 * Camera Operator: John Winbolt
 * Wardrobe Supervisor: Laura Nightingale
 * Musical Director: Edwin Astley
 * Music Editor: Deveril Goodman
 * Composer: Theme Music: Tony Hatch
 * Continuity: Valery Norman
 * Script Supervisor: Dennis Spooner