Kagamijima, an island closest to the sky.

Along with the Lake Mikagami waters that reflect the sky like a mirror on its waters, lies a soaring sakura tree in Kagami Gakuen.

Kujou Souma, who attends Kagami Gakuen. Yasaka Menoa, his queen-like undesired inseparable childhood friend. Tokisaka Yukina is a big sister figure who is the student council president. Shirawaka Akari, far-beyond-reach ojousama. Yasaka Kako, Menoa's younger sister who calls Souma big brother. Suginami, a mysterious well-informed friend. Together, they live a merry fun school life.

On Kagami Gakuen, stands a curious sakura tree called "Hakari no Sakura". It has the ability to help collect student's consensus on choices. Students choose to wear white or black capes on their uniforms, and then Hakari no Sakura aggregates the number of wearers to choose the majority. In the latest chosen event (called Hakarigoto), the student has to decide whether the next school festival would be a cultural festival or a sports festival. They get to promote and win sides on whichever festival they feel is the best to enjoy. It's a natural occurrence whenever Hakarigoto happens.

Then one day. Souma visited Lake Mikagami, where there's "another sakura tree" that has never bloomed in so many years, and blooms dazzlingly. Looking up to the sky, along with the blooming petals, a young girl descends.

"Yes, you are....", whispers the mystery girl, Sakuragi Mizuha.

Meetings of the boys and girls, the fate begins to move.

While out-of-season sakura blooms, the curtain to young boys and girls' story opens.