Captain Bill Jones is flat broke when he finds a "lucky gold piece." The coin is an authentic Spanish doubloon and Jones quickly flashes it about in the city's taverns along with stories of a treasure trove of gold. Promising huge rewards, Jones schemes to get an investor to finance a treasure hunt. But when a rival captain begins to torture Bill's friends in an attempt to learn the secret location of the gold, the island explodes with violence.
Captain Calamity's screenwriter, Crane Wilbur, also plays the supporting role of Doctor Kelkey. Wilbur's impressive body of writing credits include House Of Wax (1953), Solomon And Sheba (1959), Mysterious Island (1961) and The Bat (1959) which he both wrote and directed.