In the midst of the Cold War, an American nuclear submarine mysteriously sinks near the Cayman Trough, one of the deepest parts of the ocean. In response, a civilian oil rig crew led by Virgil "Bud" Brigman is recruited by the Navy to assist in the rescue operation. Accompanied by Navy SEALs and Bud's estranged wife, Lindsey, a project engineer who designed the rig, the team descends into the depths aboard the undersea platform. Plagued by logistical and personal tensions, the group faces the daunting task of reaching the sunken submarine and searching for survivors, all while grappling with the unpredictable dangers of the deep sea.

As the team ventures further into the abyss, they encounter mysterious phenomena that challenge their understanding of the ocean and its inhabitants. Tensions reach a breaking point when the Navy SEALs' covert agenda surfaces, threatening not only the mission but also the crew's safety. Amidst the mounting crisis, the crew discovers an astonishing secret hidden in the depths, a discovery that could alter their mission and their lives forever. As they navigate through the challenges, their journey becomes not just a rescue mission, but also a profound exploration of the unknown and a test of human endurance and spirit.