Recently widowed Kyle Pratt, a Berlin-based American aviation engineer, takes her husband David's body back to the U.S. with her 6-year-old daughter Julia, aboard an aircraft Kyle helped design. Awakening from a nap, Kyle finds Julia missing, and none of the passengers or crew recall seeing her. Flight attendant Stephanie tells Kyle there is no record of her daughter boarding the flight, and Kyle is unable to find Julia's boarding pass and backpack. At Kyle's insistence, Captain Marcus Rich conducts a search of the aircraft, while the panicked Kyle is monitored by sky marshal Gene Carson.