Within everyone there exists a side preferably kept hidden, even from close friends. For the smart and popular Kyouko Hori, it’s the fact that she has to do all the housework and care for her little brother, Souta, because of her parents' busy work schedules. For the gentle Izumi Miyamura, whom everybody sees as an otaku, it's his nine hidden piercings and large body tattoo. So what happens when they accidentally discover each other's hidden sides? Sharing parts of themselves that they couldn't with anyone else, strong bonds of friendship soon begin to form between Miyamura and Hori, as well as those around them. As their hidden personas start to dissipate, they slowly learn how to open up to others.

Shortly before the start of a new semester, Misaki Fujioka visits her twin sister Mei Misaki in Yomiyama City. The girls make full use of the last days of summer, roaming around a heat-weary town and visiting various places including a shopping center and shooting stall. When they prowl around her basement, Mei expresses uneasiness about her new class, which is said to be cursed. Craving more entertainment, the twins decide to pay a visit to the local amusement park. But the leisure of a sleepy summer day could soon turn woeful as Mei sees the color of death on her sister—an unmistakable omen that a tragedy is bound to strike. [Written by MAL Rewrite]

In 2039, helper androids are widespread as general purpose electronics. Keiichiro lost his family in a traffic accident and retired from his band. One day, he finds an android of an old model in a garbage dump. He takes her home, but after taking her to a repair shop he was told that she couldn't be repaired, so he plans to throw her away. The next day, Keiichiro finds her making breakfast for him. Thus begin the summer days of an android with no memories and a dreamless boy.

To encourage Nagi to swim and enjoy summer, Maria invites various friends to their Sanzenin family's private beach. While everyone is having fun, Nagi hesitates to wear swimsuits and come out because of her small breasts, and refuses to join...