People mysteriously start receiving voicemail messages from their future selves, in the form of the sound of them reacting to their own violent deaths, along with the exact date and time of their future death, listed on the message log. The plot thickens as the surviving characters pursue the answers to this mystery which could save their lives.

Yoriko Sudo believes in a new religious group Midoriinochikai, that worships water. She lives peacefully, devoting herself to the group daily.