Recently widowed Berlin-based American aircraft engineer Kyle Pratt is taking her husband David's body back to the U.S, after his untimely death. She and her six-year-old daughter, Julia, are flying aboard an Aalto Airlines Elgin 474, an aircraft Kyle helped design. When Kyle awakens from a short nap, Julia is missing. None of the passengers or crew recall seeing Julia. Flight attendant Stephanie later claims there is no record of Julia boarding and the passenger manifest registers the child's seat as unoccupied. Julia's boarding pass and backpack are also missing. Kyle insists that Captain Marcus Rich conduct a thorough search of the plane.