Synopsis

A mysterious invitation was sent to a group of four high school classmates. The sender is Takaki Noriko, a fellow classmate of the four who went missing five years ago.

Back in high school, Noriko was excellent in her grades, had strong sense of justice, was polite, but did not allow others to break rules. Her sense of justice gradually became abnormal when the girls reunited when they turn into their thirties. The four classmates couldn’t handle the way their lives were being controlled by Noriko and decided to kill her by pushing her off a cliff. They kept the murder a secret and continued to live peacefully until the appearance of the invitation five years later.

Who is the one behind the invitation? Does the person know the truth about Noriko’s “disappearance”? Or is Noriko alive?