When the American clipper ship The Queen is attacked by pirates off the Hebrides in 1830, Mate Kirk Hamilton (James Arness) is injured and must be put ashore at Queensland Colony, Australia for treatment and recuperation. There, he meets and falls in love with Elaine Jeffries (Kasey Rogers), daughter of the magistrate (Pierre Watkin) and all-but-fiancée to rancher Martin Shannon (Bill Kennedy). She also finds herself attracted to Kirk, and a rivalry develops between the two men. Meanwhile the pirates, led by Captain Hackett (Rye Billsbury), decide to raid the colony and in the process kidnap Elaine and her friend Nancy (Jane Harlan). Kirk and Martin lead the pursuit, having not only the romantic triangle to resolve, but the pirates to overcome and, along the way, being stranded on a volcanic island inhabited by dinosaurs.
Just 7 years before the production of this film, James Arness was severely wounded in his right leg by German machine gun fire during WWII in 1944, requiring a year-long hospital stay and multiple surgeries. The screenwriters worked his permanent limp into the script when one woman was rambling on about the “Yankee Sailor” and that she liked the way he walks, and especially the way he “limps”.