FBI agent Flynn (Samuel L. Jackson) is on a mission: transport a federally protected witness from Hawaii to Los Angeles so the government can put a brutal Mob boss behind bars. But just as the plane reaches 30,000 feet, hundreds of venomous snakes are unleashed, causing violent mayhem as the vicious predators attack everyone in sight. With the help of L.A.'s leading snake expert on the ground, Flynn leads the other passengers on a desperate, action-packed flight for their lives.