Libby needs a break. Three years ago, her husband split, leaving her to raise their infant son Ethan alone. Now for the first time in years, things are looking up and she and Ethan are going on a much-needed vacation. So why can't she stop looking over her shoulder? Is it because Libby's never told anyone the full story of what happened when Ethan was born? On vacation, Ethan wanders into an elevator before Libby can reach him. When the elevator doors open, Ethan is gone. Hours later, Ethan is seen with a woman stepping through an emergency exit. The police track the woman down, but she refuses to release Ethan. Asked who she is, the woman replies: "I'm his mother."