Following capture in World War 1, German U-boat Commander, Karl Dönitz, spends his exile developing ‘Wolfpack tactics’, hoping one day to return to the fight against the Royal Navy.
Under the growing threat of another European conflict, Royal Navy commander, Gilbert Roberts, devises wargames of his own but his career is cut short when he contracts tuberculosis. With the rise of Adolf Hitler to power, Germany reconstitutes its U-boat force, now commanded by a man returned from exile, Karl Dönitz. In Britain, the woman who will frustrate his strategies prepares a group of bright girls for a naval career. Amongst them, Jean Laidlaw, who will become one of the greatest wargamers of her generation.
When World War 2 breaks out, The Royal Navy must act before Dönitz’s top U-boat commanders starve the country into submission.