Diana 'Steve' Escott-Stevens knows what she is getting herself into. For 12 months she has fed and looked after agents preparing for a mission in France. She knows that only half of them will come back. But she is young, brave and moreover speaks fluent French. When she applies to become an agent for the Special Operations Executive she is readily accepted and sent off for training to prepare her for the field. The training is demanding; sabotage, codes, hand-to-hand combat, parachute jumps. But it is only too quickly that she finds herself in a Lysander flying to France, where any mistake could mean capture, torture or death, for her and others.