A treasure hunting crew bites off more than they can chew in this underwater white-knuckle thriller. Levi, a British expat diver, has been searching for the wreck of the USS Charlotte for his entire life. Assisted by US college graduate Noah, the pair may have finally made a breakthrough in the wreck’s location. Their crew expands after Noah’s college friends visit the duo, but as the group find themselves trapped in the darkness of the USS Charlotte’s interior, air rapidly running out, they discover that their dwindling oxygen supply is the least of their fears.