A party boat on a canal in Berlin at dawn: only a few last guests are still on board.
Suddenly one of them notices that the boat has left its landing and is now drifting off into the open sea. All communication with the mainland has been lost and the five characters are trapped.
Soon a powerful force that seems to come from the depths of the ocean, jolts the boat and almost makes it tilt. The passengers believe to see a monstrous thing, a sinister creature from the sea.
Torn between tremendous fear and the will to survive, fascination as well as disgust for the creature, the passengers become more and more unpredictable, the conflicts more and more violent and disaster takes its course.