Azusa Nakajou and her fellow graduates head to Okinawa for their graduation trip, and Tatsuya and Miyuki Shiba are bound for the same island: Shizuku and Honoka have invited them to the completion party for a newly built artificial island off Kumejima. While the others enjoy the holiday, Tatsuya is under orders to stop a covert-operations magician who defected from the Great Asian Alliance before he can strike. Working alongside the Independent Magic-Equipped Battalion, he finds an unexpected ally in a magician who used to be an enemy.