Flying at 40,000 feet in a cavernous, state-of-the-art 474 aircraft that she designed, Kyle Pratt faces every mother's worst nightmare when her six year-old daughter, Julia, vanishes without a trace mid-flight from Berlin to New York. Already emotionally devastasted by the unexpected death of her husband, Kyle desperately struggles to prove her sanity to the disbelieving flight crew, pilot, and passengers while facing the very real possiblity that she may be losing her mind.