In Class 2-3, a group of boys share a hidden secret - they belong to the clandestine Himiko Natsuno fan club. Dedicated to supporting their classmate Himiko, a valiant battle angel defending humanity from otherworldly threats, the club operates in secrecy. Hayashi, the club leader and class representative, strives to maintain their covert activities. However, their covert world is disrupted when Daichi Oogami, a new male student, joins their class, putting their secrecy at risk.