One night, young Gen Minahiro escapes from a reformatory with only one witness: the moon.
Years earlier Gen, now nicknamed Don-chan, spends his days with Tetsuya. The two are inseparable and enjoy themselves playing with Don-chan's ability to guess people's thoughts and portray them through drawings.
Then comes the day when they meet their mysterious foreign neighbour Mr Coldman, and his sickly daughter Emi.
They quickly become friends and, beneath a benevolent moon, Don-chan promises to portray her every year for her birthday.
Years later, a terrible event radically changes their lives...