For U-boat hunters, shocking sounds from the deep… It is World War 1, a time of unparalleled trial for men and their machines. The US Navy is scrambling to bring its fledgling air power to sea. The U-boat onslaught must be stopped. Naval aircraft join destroyers, sub chasers and allied submarines to protect convoys. As submarines and aircraft test one another in battle for the first time, bizarre situations can be found on all sides. Navy pilot Aidan O'Neil just wanted a chance to fly against the enemy; he wasn't looking for qualms over a German submarine's ghostly crew. U-boat crewman Adelbert Myrich was haunted by claustrophobia; and there he was, entombed in a doomed submarine. Ted Desmond would never lend a hand to the hated British; so why put life and limb on the line to rescue one of them? And Charlie Livingstone, that ever-cautious and capable aviator, throws all of it aside in a ferocious fight to save his men and his ditched flying boat. And all the while, in the background of this War to End All Wars, there are those three unique love affairs: three young couples who are convinced that their lifetime promises will survive whatever obstacles war might place in their paths.