In the depths of the ocean, a group of researchers discovers an ancient and mysterious Soviet submarine. Curious to uncover its secrets, they decide to explore the find, unaware that they have released something terrifying. Soon, the team realizes that the true threat is not only the hostile environment surrounding them but also a strange and deadly creature that has been waiting for the perfect moment to strike.
As the scientists, led by the pragmatic and determined Bud, attempt to unravel the nature of the being lurking in the darkness, tensions among them begin to escalate. Suspense, paranoia, and horror intertwine, as the creature leaves a trail of destruction in its wake, turning Bud's companions into vulnerable prey. With each encounter, fear grips the group, and their differences become more pronounced.
As team members vanish one by one, Bud must make difficult decisions to survive. The claustrophobia of the underwater environment and the relentless assault of the beast leave little time. Desperation takes hold of the crew, who realize that their only hope of escaping alive is to confront the creature and uncover the truth behind its origin. The film is a terrifying journey into the unknown, where survival becomes a struggle against forces that defy nature itself.