In May 1944 Louise Desfontaines (Sophie Marceau), a member of the French Resistance, flees to Spain after her husband is killed, where she is captured and later expatriated to London.

She is recruited by the Special Operations Executive (SOE), the secret spy and sabotage service initiated by Winston Churchill.

Louise is given an urgent first mission: to extricate a British agent (Conrad Cecil) who has fallen into German hands while preparing the invasion of Normandy.

When it comes to recruitment, anything goes: lies, blackmail, bribery (through the offer of remission of a death sentence) and calls to carry out patriotic duty.

They are obliged to return to Paris, where the SOE gives them a new, almost suicidal, objective: to eliminate Colonel Heindrich, one of the key figures of Nazi counter-espionage.