Kasumi goes back to her hometown for the first time in 6 years. She is going to see her younger sister Natsumi perform in a stage play during a festival. Kasumi herself was traumatized when she performed in a stage play club. On the day of the stage play festival, Natsumi asks Kasumi to bring her bag to the theater. The bag has a mask that Natsumi needs to wear during the final moments of the play. During the play, Natsumi's bag is stolen and a note is left behind. The note states "if you want the bag back, come to the big baseball park in town.