Every year the flowers bloom. Mysterious Cherry Blossoms blooming all over a crescent shaped island. That island is the island of Hatsune... 
The main character who goes to Kazami Academy, Asakura Junnichi, has the power to see the dreams of other people in his sleep. He was also taught magic by an old lady that allows him to create sweets. 
One day, Junnichi seems to have seen someone's dream again while he was sleeping. Inside that dream, a girl who was a childhood friend of his appeared. But, he was woken up by his sister Asakura Nemu, forcing him to come back to his regular life. Nemu doesn't actually have any blood relation to Junnichi but their bond is deeper than other real brothers and sisters. So deep that it gives the illusion that they're lovers. 
It was another peaceful normal day waking up early in the morning and going to Kazami Academy. Together with childhood friend Amakase Miharu, the academy idol Shirakawa Kotori, the two sisters Mizukoshi Moe and Mako who prefer eating nabe on the school roof for lunch. Going through their day as usual, their childhood friend, Yoshino Sakura, who they thought had moved to America suddenly appears. It was a surprise for Junnichi and Nemu. Sakura tells them, "I came to finish the promise we made during our childhood"... 
(Source: AnimeNfo and AniDB)