Majipuri -Wonder Cradle-

One day, the protagonist Makoto Himekawa was going to his school, Shiroha Academy, when he came upon a girl going crazy by a vending machine. He went to help her, but ended up drenching her in soda instead. After a light argument, the protagonist christened this girl "Trouble Woman". Due to this he was late for school, and barely made it to homeroom. And there, it seemed that there was an exchange student. But that exchange student was ... the "Trouble Woman"!

Thus, with the appearance of the exchange student Yuuri Ashitaba, Makoto's ordinary school life took a sudden turn for the decidedly non-boring, and through the athletic festival, the cultural festival, and even the autumn leaf festival, the chaos of his life quickly increased. And then, he was swallowed up in an unexpected incident ...

[From insani]