Capt. Sam Moran, skipper of a Honolulu fishing boat, receives an urgent phone call for help from his teenaged halfcaste daughter, Dee, but she is found dead on the beach before he can reach her. Sam begins making inquiries in an attempt to track down the murderer. As a result, he is beaten by the henchmen of Kryder, the playboy who introduced Dee to narcotics and then had her killed. Kryder's men burn Sam's boat, thus causing Sam's good friend Charlie Lightfoot to be severely burned while trying to save it. Sam takes the dying Lightfoot back to his Kona home and agrees to help provide additional income for his friend's sister, Kittibelle, by training her nephew Tigercat to operate Lightfoot's boat. Kittibelle needs the money to support a run-down resort she operates for the rehabilitation of alcoholics. Among Kittibelle's reformed drinkers is Melissa Hyde, an ex-marine biologist who once was Sam's girl friend. Kryder orders a big luau prepared at Kittibelle's resort and makes plans to kill Sam at the party. Meanwhile, Sam forces one of Kryder's henchmen to confess his boss's part in Dee's murder. He then pursues Kryder and his thugs at the luau and eventually shoots Kryder in the shoulder with a harpoon gun. The police arrest Kryder and his men, and Sam and Melissa decide to make a fresh start together.