In the seaside city of Riverfield stands Decelis Academy, home to seven mysterious boys sharing the same secret: They're vampires, hiding their murky pasts. When Sooha, a female student who hates vampires, transfers to the academy, the boys find themselves irresistibly drawn to her. As strange events shake the city, old sins and buried secrets resurface, and their world begins to fracture.

Every morning, Sakuradaimon-kun enforces the rules at the school gate, stopping Poem-chan for her too-short skirt. But when they’re thrown together in remedial class, she discovers his secret—the serious, uptight Sakuradaimon-kun is hopeless at studying! As they clash, bicker, and stumble through school life together, the two opposites slowly draw closer and form an unexpected friendship.

Tenshi is a former choirboy who loves to sing, but can’t muster the courage to sing in front of people. So, he settles for a quiet, stress-free academic life. But his peaceful plans turn chaotic after meeting Haruo, an ex-conductor forming a boys choir to restore his name. Tenshi and others reluctantly join. Despite Haruo’s antics, they grow to love performing and aim to win the national contest!