"A girl who has not fallen in Love. A boy who isn't interested in Love. If such two persons meet, how the World will change?"

(Source: official site; edited)

This is a story related to the Mashiroiro Symphony manga and visual novel game. An all-girl's school is preparing to consolidate with another nearby school, which will make them co-ed. Uryuu Shingo is chosen to be a male 'test student' at the girl's school before they officially merge in the following year. Though there was initially some opposition by the female student body, many of them have grown to like Shingo. His greatest opposition, Sena Airi, has even gotten used to him. However, the heroine of this story, Inui Sana, still hates all men in general and Shingo in specific. But could her blatant dislike be masking some other, truer feelings?
(Source: Baka-Updates)

This is the official comic based on the game of the same name. An all-girl's school is preparing to consolidate with another nearby school, which will make them co-ed. Uryuu Shingo is chosen to be a male 'test student' at the girl's school before they officially merge in the following year. On Shingo's first day, he learns that many of the girls are not happy about the coming merger. Specifically, Seno Airi is staunchly opposed and refuses to welcome him to the school. Some of the other girls are friendly, but Airi has a lot of power over public opinion. The truth is, though, that Shingo has met Airi before. When she and Shingo's little sister got lost, he helped them find their way. Airi seemed to like him then, back when she didn't know he was going to be her new male classmate. Maybe he'll be able to win over Airi, as well as all his other interesting female classmates!
(Source: MangaHelpers)