Right from the start the whole exercise seemed doomed. When he heard he was to take part in one of Churchill's most audacious, some would say foolhardy, operations, Lieutenant-Commander Donald Cameron reckoned expendability was in the air. With a reduced complement, minimal supplies & armament, Cameron is given the command of a shaky old P-class destroyer joining two others in a similar state for the short crossing to the French port of Brest. There they are to penetrate the port & land a detachment of commandos to blow up the huge German U-boat pens. When the Senior Officer's ship is blown up & the commandos fail to make the return rendezvous a the quayside, control of the operation falls to Cameron. Knowing that German warships are in the offing, he decides to creep inland, up the shallows of the Rade de Brest & make contact with the Resistance. It may seem hopeless but to attempt a dash to sea without support would be suicidal