Penitentiary III

American treasure hunter Frye (James Earl Jones) awakens an ancient creature while searching ship wreckage off the coast of a Greek island. When news of its awakening reaches the natives, they are determined to appease the sea monster in the only way they know - by sacrificing a virgin to its ravenous appetite. In order to stop the beast once and for all, Frye teams up with local historian Nereus (José Ferrer), who has been studying the history of the monster. Now his knowledge is the only thing that has a chance of defeating the rampaging beast! (official distributor synopsis)