Halloween in a small town is cancelled indefinitely when a young girl is kidnapped and killed on her way home from a costume party. Ten years later, a detective's obsessive attention to detail exposes a shocking mistake that kept the case's most obvious suspects on the streets for 10 years.

The case of a gruesome stabbing death of a bullied teenager remains unsolved for 27 years – until a rookie cold case detective sees a new clue in an old crime scene photo, leading her to a killer that everyone thought could not possibly have committed the crime.