After surviving a shipwreck, San Diego tuna fisherman Mike Mascarenhas, an immigrant from Portugal, loses a hand to a shark. The following season, one of his crew, Manuel Silva, falls overboard and is killed by the sharks following the boat. Mike brings the bad news to Quita, Manuel's daughter. Moved by Quita's beauty as well as her lonely situation, Mike, who is unpopular with women, takes care of her, bringing her food and money. When he asks her to marry him, Quita confesses that she does not love him, but he insists that this does not matter to him and he will accept her as she is. Touched by his generosity, Quita agrees to marry him. At the wedding, however, she falls in love with Pipes Boley, a fellow fisherman who is Mike's best man. When Quita tells Pipes of her love, he plans to leave town, but before he does, he catches a fishing hook on the back of his neck and Mike brings him home to recover. While Quita nurses him, she and Pipes fall deeper in love. Quita accompanies Mike and Pipes on a fishing trip, where, overcome by her feelings, she embraces Pipes, unaware that Mike is watching. Angry, Mike punches Pipes and dumps his unconscious body into a leaking boat, where, he gloats, the sharks will enact justice. As Mike watches the sharks surround Pipes, his foot is caught in a line and he is dragged overboard, where the sharks attack him. The men pull him out and he dies of his injuries after apologizing to Pipes and Quita.