Four years ago, Julia Ashton disappeared on an archeological expedition to an uncharted island. Her two children, Walker and Kira, have been living with Erik Jones, one of Julia's former colleagues, still haunted by her mysterious disappearance.

But when an old friend of Erik shows up on his doorstep with a clue, he assembles a team to go find Julia and the island she disappeared on. As they journey across the Caribbean, the team is hunted by the Erebus Consortium, a secretive organization determined to reach the island before Erik, Walker, Kira, and the rest of the team do. They find themselves in a dangerous race against the Consortium to find Julia, and answers to mysteries both old and new.