Bishop Blackie Ryan is feeling more than a bit out of place on the USS "Langley, " an aircraft carrier on duty hundreds of miles from the nearest dry land. But the ship is in trouble - several of her crew have disappeared without explanation, and one dead officer has seemingly reappeared. The captain has a major problem on his hands. And the captain happens to be a relative of Blackie's boss, Cardinal Cronin. So Blackie, troubleshooter and problem solver, has been dispatched to the "Langley" - where he soon finds a mystery as deep - and dangerous - as the ocean all around.