Tricia's husband Daniel has been missing for seven years. Her younger sister Callie comes to live with her as the pressure mounts to finally declare him 'dead in absentia.' As Tricia sifts through the wreckage and tries to move on with her life, Callie finds herself drawn to an ominous tunnel near the house. As she begins to link it to other mysterious disappearances, it becomes clear that Daniel's presumed death might be anything but 'natural.' The ancient force at work in the tunnel might have set its sights on Callie and Tricia ... and Daniel might be suffering a fate far worse than death in its grasp.—Mike Flanagan