Kouichi Sanada wakes up and goes downstairs because of a loud knock at the door. At the door was his childhood friend Mao Mizusawa who he didn't recognize at first. A short while after Mao takes a shower, and Kouichi's other childhood friend Aihara, who also knows Mao as a childhood friend, shows up at his house too. Aihara is surprised to hear a girl in Kouichi's shower, and starts questioning Kouichi about it, until Kouichi yells out that he didn't know who she was...