在一场严重的水下洞穴事故后，幸存者们冒着生命危险，执意要回到神秘而危险的洞穴将逝去朋友的遗体找回。

A team of Finnish divers suffers a devastating loss when two of their friends don"t make it back to the surface on a deep dive in an underwater cave in Norway. After unsuccessful attempts are made by international authorities to retrieve the bodies, the cave is closed off. The fallen colleagues are left buried in dark waters. In an act of camaraderie and compassion, the team reassembles in a covert operation to bring back the bodies of their fellow divers, risking their own lives in a secret dive. The team constructs a plan that becomes a pulse-pounding plunge into claustrophobic darkness, gambling with their own safety to honour those who stood and swam by their side.