Hydra

Dr. Valerie Cammon and Dr. Kim sail toward a volcanic island in the Mediterranean to search for relics. They explore a cave that may hold ancient artifacts, braving treacherous seas. A violent seaquake sinks their ship, and Cammon survives amid the wreckage. Soon after, the Hydra awakens and consumes the other archaeologists.

During the tempest, the Hydra awakens from its long slumber and begins feasting on the unlucky archaeologists aboard. Cammon clings to debris, realizing she is the sole survivor amid the wreckage.

Two months later, Vincent and Dixie Camden prepare a man-hunt for the criminals they blame for their losses. Their Captain suggests the nearby island as a substitute hunting ground, unaware of the Hydra's growing threat.

Four ex-convicts—Tim Nolan, Gwen Russell, Bob Crick, and Ronnie Kaplan—are marooned on the shore and given a 24-hour head start to survive. They must rely on wits and teamwork to endure the looming danger from their pursuers.

The following day, the rich hunters arrive and learn that their targets are tied to crimes mirroring their own losses. They plot abducting the fugitives, unaware that the Hydra already stalks the island.

The Hydra draws the hunters’ attention and begins to feast on them, and several fugitives also fall prey to the monster. The island becomes a deadly trap as the creature closes in on its prey.

Dr. Cammon runs into the surviving fugitives and helps Tim search for the magic sword of Hercules. Her knowledge of relics becomes instrumental in guiding the quest.

Tim obtains the magical sword and prepares to face the Hydra. Cammon distracts the beast to buy him time, but she is killed in the attempt as the monster closes in.

Tim hacks at the Hydra, severing several heads, but the last head remains active and the beast still threatens the survivors. The group has to press on without Cammon’s guidance.

With Cammon dead, Tim and Gwen return to their ship, unaware that the Hydra is following and has become a one-headed, serpentine predator. The creature coils into the ship’s passages, bringing the danger aboard.

Gwen attempts to use the radio to call for help, but the microphone is damaged. Mr. Camden blindsides her and uses the moment to threaten Tim, stirring tension among the survivors.

The Hydra strikes from behind, killing Camden and then devouring Dixie as the threat intensifies aboard the ship. Tim seizes the magic sword again, preparing for a final confrontation.

Tim engages the Hydra in a climactic duel and finally slays the beast, ending its menace for good. The survivors are left to reckon with the cost of their ordeal.