Eight-year-old Sophie Donohue just wanted to be like every other little girl. Which is why her mother, Janine, reluctantly agreed to let her go on the weekend camping trip with her Brownie troop. But when Janine arrives to pick up Sophie after the trip, her daughter is not with the others. Somehow, along the forested route from West Virginia, Sophie has disappeared.

Sophie is no ordinary eight-year-old. She suffers from a rare disease, and Janine has recently enrolled her in an experimental treatment as a last effort to save her life—despite the vehement objections of her ex-husband, Joe. Without her medication, Sophie cannot survive long. All her mother's instincts tell Janine that Sophie is alive, but time is running out.