On the eighth anniversary of a cult’s failed chemical attack on Tokyo and their subsequent mass suicide, family members of those affected gather at the cult’s former base on the shores of a lake to observe the anniversary of their loved ones’ deaths.

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 persue the answers to this mystery which could save their live