A schooner disappears at sea without a trace. Years later, evidence of possible survivors prompts the mother of the schooner's mate Jose to hire a tuna boat to investigate. They discover the lad living happily on a South Seas island, and, when he refuses to leave with them, they abduct him. However, Jose gets revenge by leading the ship into the lair of a mysterious giant manta ray.
Barry Norton
as Robert Jackson
Blanche Mehaffey
as Louise
Jack Barty
as Capt. Jackson
Terry Grey
as Tiny
Jack Del Rio
as Jose Francisco
Mary Carr
as Mother of Jose
