In 1928, in Los Angeles, the United States, Christine Collins (Angelina Jolie), who worked at the telephone switchboard, raised her son Walter (Gattlin Griffith) alone. The life of mother and son was simple and happy. However, their lives were soon disrupted. One day when Christine got off work, she found that her son was missing. Under the pressure of public opinion, the corrupt Los Angeles police found Walter five months later, but Christine found that this was not her biological son. She repeatedly asked the police to clarify the facts and help them find the real Walter, but she was obstructed and accused again and again, and was even sent to a mental hospital on the charge of obstructing the police's duties. Pastor Gustav Briglab (John Malkovich), who has always been committed to exposing police brutality, ran around for the unfortunate experience of this poor woman. On the other hand, while investigating a smuggling case, Detective Lester (Michael Kelly) accidentally discovered a major serial child murder case. The disappearance of young Walter seems to be gradually revealed...