In the small Iowa town of St. Luke, in the sleepy summer of 1953, Lizzie Harris is about to turn eight. Lizzie, an unrepentant tomboy, has one fervent birthday wish-a real hunting knife-a knife she dreams of incorporating into the endless imaginary adventures she shares with her best friend Robert, the gifted but haunted seven-year-old who lives next door. But while Lizzie's rock-solid family life frees her to inhabit her childhood summer untroubled by dark anxieties, Robert is not so lucky. The house next door seems to harbor a frightening secret that leaves Robert looking back over his shoulder in fearful uncertainty. Then one quiet summer evening, the children's world is shattered by a terrifying incident that hurls Lizzie and Robert together in a race for their lives.