"1944, two weeks before the Allied landings in Normandy. The home front is riddled with German spies, and the Reverend Colgate-Jones of the little town of Claybury, along with his old colleague and head of the Secret Service Michael Dene are about to uncover a nest of them.
The words 'tooth paste' are the key to Britain's survival from an impending sabotage led by the arch German spy known only as X.1.
These ordinary words, conveyed to Dene and Colgate-Jones by a dying colleague, are a signal to the Third Reich and its operatives in England to attack on the 21st of the month. Only a week away. X.1 must be tracked down and stopped. His plan must be uncovered. The fate of Britain is at stake."