A red-eye flight from LAX to Nashville takes a terrifying turn of events when the passengers become infected with a highly contagious virus, and find themselves quarantined in an airport following an emergency landing. Picking up immediately after the events depicted in Quarantine, this relentlessly tense sequel finds the passengers of Flight 318 ascending into the clouds as reports of a sequestered L.A. apartment building begin filtering though the nightly news. Shortly thereafter, the passengers on the flight begin to exhibit disturbing rabies-like symptoms, forcing the pilots to make an emergency landing at an isolated terminal in a large metropolitan airport. As the group hastily departs the plane, terrified flight attendant Jenny (Mercedes Masohn) bravely attempts to lead them to safety. But when a squad of police officers and emergency workers arrive on the scene accompanied by the CDC, the passengers' relief turns to horror as they realize they have been quarantined, with no hope of escape. Now, their only chance of living through this nightmare without getting infected by the virus or shot down while fleeing rests in the hands of Jenny and resourceful kindergarten teacher Henry (Josh Cooke), who try to remain calm long enough to formulate a viable escape plan.