Mark Hawkins, former park ranger and expert tracker, is out of his element, working onboard the Magellan, a research vessel studying the Great Pacific Garbage Patch. But his work is interrupted when, surrounded by 30 miles of refuse, the ship and its high-tech systems are plagued by a series of strange malfunctions and the crew is battered by a raging storm.

When the storm fades and the sun rises, the beaten crew awakens to find themselves anchored in the protective cove of a tropical island...and no one knows how they got there. Even worse, the ship has been sabotaged, two crewmen are dead, and a third is missing. Hawkins spots signs of the missing man onshore and leads a small team to bring him back. But they quickly discover evidence of a brutal history left behind by the island’s former occupants: Unit 731, Japan’s ruthless World War II human experimentation program. Mass graves and military fortifications dot the island, along with a decades-old laboratory housing the remains of hideous experiments.

As more crew members start to disappear, Hawkins realizes that they are not alone. In fact, he suspects they were brought to this strange and horrible island. The crew is taken one by one, and while Hawkins fights to save his friends, he learns the horrible truths: Island 731 was never decommissioned and the person taking his crewmates may not be a person at all - not anymore.