The year is 1830. The American clipper ship, the Queen, is attacked by pirates in the New Hebrides (present day Vanuatu). The ship's mate Kirk Hamilton (Arness) is wounded and heads to Queensland, Australia for medical treatment. While at the hospital, he meets and falls in love with Elaine Jeffries (Rogers), the fiancee of Martin Shannon (Bill Kennedy (actor)) a rancher. A romantic rivalry develops and the pirates, who attacked Kirk and his ship kidnap her along with her friend, Nancy Holden (Jane Harlan). Kirk and Shannon pursue the pirates and they soon wind up on a volcanic island inhabited by dinosaurs.