George Darcy and Tim Ryan, rival gang leaders, find themselves working on the machinery of a U.S. Navy ship during World War I. For a time, their rivalry over politics and a young woman named Rose is put to rest by shipboard discipline, but the ship's chaplain, Father Joe, finally decides to have them meet in a ring. The fight is interrupted by a submarine attack, but the attack is repelled. After the war, their feud continues until drug dealers kill one of George's brothers and a friend of Tim's. Together, George and Tim attack the dealers' hideout and blow up their submarine. Later, under Father Joe's auspices, a fight is arranged between them, and George emerges victorious.
