One autumn day, a transfer student from a foreign country showed up in Oshi's class, a second-grader at junior high and this story's main character.
The girl with short silver hair and striking azure eyes called herself Mai.
Although her Japanese was a bit rough, her polite demeanor and elegant appearance quickly captured the attention of the entire class.
However, something about that attitude everyone loved gave the protagonist a sense of unease.

One night, on the way home from dinner with his aunt and her family, the main character hears the beautiful singing voice of a girl amidst the residential area.
Even though it was a wonderful voice, her song sounded out of tune. Intrigued, he started walking in the direction of the noise...

In an empty lot, he finds his foreign classmate singing under the moonlight.

There, the protagonist discovers a secret about Mai, and so marks the beginning of a strange school life between the two.

[Translated from the official website]