Beyond Atlantis

A man brings Syrene to an island and she pays him with pearls. The islanders have oversized eyes and appear inbred, and they kill any intruders they find.

Back on the mainland, Manuel the Barracuda pays East Eddie with pearls. Eddie shows the pearls to Logan and the two decide to hunt for the source, hoping to profit.

Logan meets Vic Mathias, who has a boat, and they strike a deal to use the boat to search for the pearls. They plan to leverage the boat to reach distant pearl beds.

Dr. Katherine Vernon overhears the plans and talks to Logan; she agrees to meet him the next day. At a museum, she explains she wants to find the pearls solely for their scientific value.

The party sets off for the island and confront Manuel the Barracuda to learn the route to the pearls. They reach the island and begin their search for the pearl beds.

They encounter Syrene and her people, who can live both on land and in the sea, and she agrees to reveal the pearls' location. However, Syrene and her father Nereus want to mate Syrene with one of the group—specifically Vic.

She leads them to beds of pearls and the first mate is mysteriously killed as the plan unfolds. Vic wants to leave, but Logan and Eddie insist on one more dive to secure the treasure.

Syrene enraptures Vic and they mate, aligning with Nereus's plan to merge with the outsiders. The rest of the crew grows wary of the perilous alliance.

Nereus decides that the outsiders must die; Vic, Logan, Eddie and the crew fight their way back to their boat. The struggle pits the group against the sea natives as they retreat.

Katherine is attacked by Syrene, but Syrene is killed, ending any chance for the sea people's lineage to continue. The expedition's danger subsides as humans reclaim control.

They march into the sea with the pearls as a dangerous prize. Logan lifts a blanket of pearls from Syrene's funeral bier, suggesting a glimmer of hope for recovering the treasure.

Manuel arrives to double-cross the survivors. A fight breaks out and the case of pearls falls overboard; Logan convinces Eddie and Vic that the pearls can be found again.