 Riding his motorcycle in Hawaii, Sean Jones witnesses the brutal murder of a prosecutor. When the villains come to take out Sean, Agent Nelville Flynn comes to his rescue. In order to protect Sean for the trip back to L.A., Flynn takes over the entire First Class section of Pacific Air Flight 121. Displeased First Class passengers aside, the flight is uneventful until hundreds of angry, poisonous snakes are released into the cabin. Once the snakes begin attacking, it is up to Agent Flynn and Sean to keep the plane in the air and save as many passengers as they can.