Meet Lieutenant Peter Harding as he proves himself in submarine warfare against the cunning of the German U-boats as the tumultuous events of the Second World War unfold.BOOK 1: SHADOW (prequel)1940. Peter Harding joins HM Submarine Shadow for his first tour of duty. Shadow is not a happy ship, ruled by an overbearing, unlikeable commander. But Harding learns rapidly, and the fortunes of war dictate changes in both his and Shadow's future.From infiltrating the fjords of Occupied Norway to stalking U-boats on the Mediterranean convoy runs, Shadow becomes both hunter and hunted in the deadly undersea war.BOOK 2: COMMANDFrozen fingers, broken bones, shattered hearts . . . the situation could not get worse.Or so Lieutenant Peter Harding thought. The Trigger has just left British shores and is on its way to northern Norway when the relentless storm hits. Harding's crew are barely surviving the Arctic conditions which face them. The ship is slowly dying and cracks are beginning to show, in both the ship and in relations between the men on board.The navy of Nazi Germany are under orders to destroy The Trigger, but how much will it take before Harding and his men surrender to the enemy?BOOK 3: TRIGGERDeep beneath the placid Mediterranean, the submarine Trigger stalks the enemy convoys . . .Lieutenant Peter Harding is one of the most successful commanders in the Fleet. But no man's nerve can last forever - and Harding's is beginning to crack. But the Admiralty has its own ways of securing Harding's continued service. And it has one further task for Trigger and her crew.BOOK 4: TALONThe war in Europe is over. But on the other side of the world Lieutenant John Gascoigne takes command of HMS Talon, a submarine patrolling the treacherous waters of the Java Sea. Gascoigne is a man haunted by past loyalties; by the ever-present ghost of a woman he loves, but can never have.The constant successes of the American submarine commanders, his allies and rivals, only fuel his resentment of the present. Gascoigne is desperate for success in Talon, and he will take any risk to get results. But a Japanese destroyer is a formidable target - even when dead in Talon's sights . . .