Emily (Dakota Fanning)'s mother died in a blood-filled bathtub, and the little girl was so devastated that she fell into isolation. In order to get his daughter out of the haze as soon as possible, David (Robert de Niro) moved to the country with his daughter. Here, Emily met her new friend, Charlie, who had been playing hide-and-seek. But no one but Emily knew who Charlie was, and he seemed to be living in the illusion of his daughter and wandering around them. With the occurrence of terrorist incidents one after another, Emily became more and more dazed, and David gradually realized the seriousness of the problem. He began to record his daughter's words and deeds, hoping to prevent Charlie from getting close to her. But who on earth is Charlie? Where is he hiding?