Screenplay by PHILIP BROADLEY   Directed by ROY WARD BAKER     The Champions have to work out how to break into a top security vault, and it’s programmed to kill...     Lord Mauncey (DAVID LANGTON), wealthy and highly placed, is one of the nine people to have access to a top security vault operated by M.7.—a vault which contains vital NATO documents. Why, therefore, should he try to break into the vault? He gets as far as obtaining the secret file, but is caught because he is unaware that type on the file is magnetised and that it operates an alarm system the moment it is moved from the vault.   Mauncey’s only explanation is that he took the file on impulse. He cannot explain why. But what worries Duncan (WILLIAM SQUIRE), the head of M.7, is that the vault is not so impregnable as he imagined, and Nemesis is asked to test the security system in case Mauncey has handed the secret to a foreign country.   Craig (STUART DAMON), Sharron (ALEXANDRA BASTEDO) and Richard (WILLIAM GAUNT) have the task of testing the system, with the warning that the last safeguard, if any intruder appears to be getting away with the file, is that the system is programmed to kill...   It really is a nutcracker to handle, and they decide to break into Duncan’s office to see if they can find details of the electronic code. They find it so easily that it might have been deliberately placed there for them. Is this part of Duncan’s plan and, if so, what lies behind it? Is he, in fact, also a traitor? Evidence mounts up that he is.   With the others watching events from the outside, Richard takes the risk of stealing the file. It’s a tense, dangerous experience which meets with complete success—except for one secret he keeps to himself—a secret which may well trap Duncan if he is, indeed, the guilty man.   Lord Mauncey, despite Sharron’s efforts to make him talk, refuses to do so or to admit that he is in the pay of a foreign power. But when he is murdered, the case takes on even more sinister implications.   The Champions find one link between Mauncey and Duncan. Both have been attending the same dentist, a man named Warre (JOHN FRANKLYN-ROBBINS). But Warre and his colleague, Travers (DAVID KELSEY) and Walcott (JOHN BROWN), are by no means orthodox dentists...     AN PRODUCTION   Series created by Monty Berman and Dennis Spooner   © Copyright Incorporated Television Co. Ltd. MCMLXVII     Stuart Damon   Alexandra Bastedo   William Gaunt   Anthony Nicholls     Craig Stirling   Sharron Macready   Richard Barrett   Tremayne     William Squire   David Langton   Michael Barrington   John Franklyn-Robbins   John Brown   David Kelsey   Dennis Ward   Robert Mill     Duncan   Lord Mauncey   Manager   Warre   Walcott   Travers   Guard   Assistant     Production supervisor   Director of photography   Art director   Editor     Geoffrey Haine   Frank Watts   Charles Bishop   Derek Hyde-Chambers     Musical director   Theme composed by   Post-production supervisor   Production manager   Casting   Stunt Arranger     Edwin Astley   Tony Hatch   Philip Aizlewood   Malcolm Chistopher   Anthony Arnell   Frank Maher     Sound editor   Sound recordists     Music editor   Associate art director   Set dresser   Construction manager     Alan Corder   Len Shilton Dave Bowen   Deveril Goodman   John Graysmark   Brian Rider   Bill Greene     Second unit director   Second unit cameraman   Camera operator   Assistant director   Continuity   Special effects     Ray Austin   James Allen   Harry Gillam   Ernie Morris   Elizabeth Wilcox   Sid Pearson     Scenic artist   Production buyer   Make-up supervisor   Hairdressing   Wardrobe supervisor   Supervising electrician     A.J. Van Montagu   Sid Palmer   Gerry Fletcher   Michael Jones   Laura Nightingale   Ted Hallows       Made on location and at ASSOCIATED BRITISH ELSTREE STUDIOS ENGLAND.