Former soldier Bob Etheridge sends, a letter from his death bed, to a senior servant Gerald Jackaman who shots himself. The government fear nuclear strategist Prof. John Tyler and Jackaman are linked so second SAS Major Harry Maxim to him.
Maxim is in hiding with Czech defector Zuzana Kindl, following a shoot out at Paddington Station. She says there is a mole in Secret Service known as "The Roofman" but is killed. Maxim goes in search of letter written by Bob Etheridge.
The Etheridge letter is lost in a explosion. Aggie finds the SAS men in the photo but only Col. de Carette survives. He tells of how Tyler once resorted to cannibalism to survive. In Luxembourg, Maxim finds someone is still covering up.
