Meg Landry expected it to be a day like any other -- her asthmatic eight-year-old son would step off the bus, home from school. But on this day, the boy on the bus is not Meg's son -- or at least doesn't appear to be. This new boy shares Charlie's copper hair, tea-brown eyes, and slight frame. But there is something profoundly, if indefinably, different about him. He has a finer nose, his skin is shinier, and his face looks more mature, as if he has grown into being Charlie more than the real Charlie ever had. In the wake of Meg's quiet alarm, her far-flung family returns home, and a jangly unease sets in. Neither Charlie's father, Jeff, nor Charlie's rebellious teenage sister, Katie, can help Meg settle the question of the boy. They look to her for certainty -- after all, shouldn't a mother know her own child?