Ritsuko discovers an old cassette tape, while packing her things to move into a new apartment. She listens to the tape and hears the voice of a frail girl saying "I'm so afraid of tomorrow that I can't fall asleep. I think I'm going to die soon." Soon after, Ritsuko leaves a sparse note for her fiance Saku, "I'm going away for a while. Don't worry about me. - Ritsuko." During this
