Returning from France, Gallagher begins to compile a team of specialists to train for a one-off mission behind enemy lines. Not everybody is convinced that some can be trusted to follow orders.

Following a nighttime jump, the unit rendezvous at Pierre de Grouchy's farmhouse. Meanwhile, Gallagher discovers a traitor in the Resistance while former nightclub singer Simone could be recognised.

The unit has now been reduced to six specialists who will participate in the raid. Lovell is determined to quit but no replacement can be found. His superior Professor Evans is brought in to help change his mind.