After witnessing a brutal murder instigated by Honolulu-based California gang boss Eddie Kim on prosecutor Daniel Hayes in Hawaii, Sean Jones is escorted by FBI agents Neville Flynn and John Sanders on a Boeing 747-400 to testify in a trial against Kim in Los Angeles. Despite increased security for the flight, Kim arranges for a time-release crate full of venomous snakes to be placed in the cargo hold in an attempt to bring down the plane before it reaches Los Angeles International Airport (LAX). To ensure the snakes attack the passengers without the need for provocation, he has one of his henchmen disguised as an airport ground employee spray the passengers' leis with a special pheromone which makes the snakes highly aggressive. The crate opens midway through the flight and the snakes make their way through the cabin. A couple having sex in a bathroom and a man using another bathroom are the first people killed. The plane's captain, Sam McKeon, investigates and fixes an electrical short, but is killed by the viper that caused it. Co-pilot Rick, unaware of the snake, believes Sam has suffered a heart attack and continues toward LAX.