Ep. 1: Kouichi reunites with childhood friend Mao Mizusawa after she arrives unexpectedly at his home.

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Kouichi Sanada answers a loud knock to find Mao Mizusawa, a childhood friend he initially fails to recognize. After Mao showers, another childhood friend, Aihara, arrives and is surprised to hear a girl in the bathroom, prompting questions that Kouichi cannot answer. Mao exits the bathroom upset that Kouichi does not remember her, but both she and Aihara eventually recall her identity. That evening, Mao and Kouichi play video games late into the night. The following morning at school, Mao encounters a mysterious quiet boy, Kouichi is surprised by an unspecified event, and Aihara receives a kiss from the famous genius girl Futami.