Exploring the bottom of the ocean is scary. It's worse when something down there is stalking you. Off the coast of New Zealand, there's an underwater mining facility, 8,000 feet under the ocean. The crew stationed there knows that drowning is the least of their worries at such depths. That's why they panic when a maintenance member goes missing while out on a repair mission. He had only eight hours of oxygen, and almost a day has gone by since they lost contact, so the crew can only hope to retrieve his body. Then they receive a distress call from him - at a depth of 11,000 feet. A small rescue team suits up and dives to find their missing crewmate. But descending into the unforgiving depths of the ocean is much easier than going back up, and the team learns that too late. Now, stranded at the bottom of the trench without the ability to call for help, they realize that coming down here was a terrible mistake. There's something far worse down there than the crushing pressure, the ticking timers on their oxygen tanks, and the everlasting darkness that inhabits such depths. And it's haunting them one by one.