It’s 1942 and a fleet of German mini-submarines are loose in the Mediterranean wreaking havoc on Allied shipping, sinking urgently required supplies destined for Malta and Alexandria and the new invasion beachhead in Algeria, thus jeopardising the squeezing of Rommel out of North Africa. Awaiting an ETA regarding a large American convoy, they are re-arming and refuelling at their base in Vichy France near the Spanish border. Can the British commandos en route in motor gunboats reach the port in time to destroy the vessels or will they fall foul from information supplied by a suspected spy at the War Office in London and die like so many Special Operations Executives, agents and resistance fighters in various recent missions? Perhaps the best chance of success lies with S.O.E.’s secretly arranged mission involving their French agent Pierre Duvalle, seconded to a special boat section of the Royal Marines and transferred by submarine to within striking distance with five experienced and lethally efficient men of that elite force. Three two-man folboat canoes would see them to their target. But what does the informer in London know? Will Duvalle, who has a very sad and personal reason to see him exposed, find a chink in the spy’s armour?