A family reunion at a remote mansion takes a lethal turn when they are trapped inside and forced to play a deadly survival game where only one will make it out alive....
Nightclub singer Larry Todd breaks off his romance with a beautiful showgirl when he realizes she's the girlfriend of a murderously jealous gangster. While on the run, Larry mistakenly believes he kills one of the mobsters and is helped to escape police by heiress Mary Carol, who smuggles Larry and partner Myron to Cuba. Mary has inherited a haunted castle on an isolated island......
When a daring mission leads a deep sea submarine team into a mysterious opening on the ocean floor, they uncover a lost underwater world and awaken its ancient race of otherworldly beings....