Story: The day before the opening of a mall it's pouring rain in Pines Valley. Sheriff Chris Maratos is worried about the stability of the McKimson Dam. On his way to the dam he gets a message about the escape of an unpredictable, dangerous criminal from a prison nearby. Maratos' fears become reality: The dam breaks and the valley where the new mall has been built is flooded.
On that night 6 persons are in the mall: Sheri Maratos, the Sheriff's wife, who is looking for a present for her husband's 30th birthday; Roger, an architect; Tom, a security guard; a clerk; Suzanne, a pop-singer rehearsing for the opening day, and her Manager, David.
When the water reaches the building, the basement is immediately flooded. Sheri, David and Suzanne manage to escape to the 2nd floor where they meet the other prisoners of the catastrophe. When they try to contact the Sheriff's office via radio, they hear a police announcement: The dangerous criminal was probably trying to hide in the mall! Soon their suspicions are confirmed: The clerk's dead body is floating past them...
A merciless killer forces Sheri and one of the other trapped people to dive in the basement and look for a suitcase full of money left behind by the escapee's accomplice. While they are risking their lives, the police discover what is happening. Supported by a SWAT-team and State Troopers, Sheriff Maratos and his people try to enter the mall....