Rennie and Knight are Polish resistance fighters during WW II who become forced laborers at Peenemunde, the location of the secret Nazi V1 factory. They gather information which is smuggled back to England and try to ambush a truck carrying one of the rockets. The attack fails but later
they find an unexploded missile from a failed test out in a field. They carry it off and have it flown back to England, where it proves to be extremely valuable to the Allies. This is an often tense and exciting war drama enacted by a talented cast.