The film follows a team of treasure hunters led by the experienced captain, played by Mark Strong, who embarks on a perilous mission to recover a sunken submarine rumored to be carrying valuable cargo. As the crew navigates through the vast, dark depths of the Black Sea, they encounter not only the dangers of the sea itself but also a terrifying supernatural presence that begins to haunt their every move.

The underwater setting adds an ominous layer of isolation and fear, with the vastness of the ocean and the mysterious force within it creating an atmosphere filled with dread. Tensions rise among the crew members as they struggle to survive and unravel the secrets hidden beneath the waves.