The “irregular” elder brother and his younger sister are about to finish their first year at Magic High School. Tatsuya, Miyuki and the others have decided to spend their spring break at a private villa on Ogasawara Island.They are making the most of their brief vacation until a young girl named Kokoa appears before them. She has escaped from the naval base and tells Tatsuya her one wish.

[Source: Funimation]