1946. The war is over-on paper. But in the cold, fog-choked North Atlantic, merchant ships are being ripped apart by torpedoes fired from a submarine that shouldn't exist. Survivors swear they saw a skull-flagged U-boat rise out of the mist and vanish like a ghost beneath the waves.

Ex-RAF pilot Jack Falcon, now a field agent for the hush-hush Department 7, is sent to hunt the phantom sub. With his gadget-wise partner Billy "Sparks" Devlin and brilliant cryptanalyst Dr Evelyn Drake, Falcon follows a trail from storm-tossed Irish harbours to the bomb-scarred docks of Hamburg and a hidden fjord base in Norway.

There they uncover a chilling truth: a renegade admiral has been financing a secret Fourth-Reich network with stolen Reichsbank gold-and he's refitted his U-boat to strike again. Pursued by assassins, trapped aboard the enemy's deck in a gale, Falcon must out-fight the admiral in a desperate conning-tower duel as Royal Navy depth-charges hammer the sea around them.

Packed with cliff-hanger action, wartime intrigue, storm-lashed sea battles, and classic 1940s pulp-adventure atmosphere, Jack Falcon and the Phantom U-Boat launches a brand-new high-octane thriller series for fans of Jack Higgins, Alistair MacLean, and vintage radio-serial heroes.