A secret formula that can cause plants and animals to expand a thousand-fold in size is stolen by a terrorist group. During a wild chase and shoot-out, the formula is lost. It's found by a little girl who accidently gives the formula to her pet snake. After the snake grows to an immense size, it follows and protects her. When the terrorists go after the girl, the snake begins destroying everything in its path. Hong Kong cut and paste edit of the 1987 Taiwanese film "大蛇王" (King of Snake) with new scenes.

An American submarine leaves Tierra Del Fuego, and one of its crew has secretly brought aboard a container full of poisonous snakes which escape storage and bite key personnel on the submarine, causing an accident that cripples the vehicle so that it drops to the bottom of the Southern Ocean. Worse still, the snakes are still at large on the submarine and complicate the efforts of the crew to escape the sunken vessel.

FBI agent Neville Flynn boards a flight from Honolulu, Hawaii to Los Angeles, escorting a key witness to testify against a mob boss at an upcoming trial. An on-board assassin releases a crate full of hundreds of deadly venomous snakes in an attempt to eliminate the witness. Flynn and a host of frightened passengers and crew must band together to survive the slithery threat.