Kotone Aizuhara, a male university student and self-identified fudanshi, possesses eleven years of deep engagement with boys' love manga, steeped in its tropes and conventions. His human life concludes abruptly when fatally struck by a truck while purchasing BL manga, instantly transporting him to an alternate world. There, he encounters Nagi, a divine serpent assuming human form. Nagi declares Kotone the summoned "chosen one" essential for his ascension to a higher dragon form, a process requiring sexual intercourse. This world lacks women entirely, operating under distinct social and biological rules where divine beasts interact with humans.

Initially resistant, Kotone recoils at the prospect of losing his virginity and occupying the submissive role dictated by the situation – a role reversal from his typical BL fantasies where he envisioned others. His extensive BL knowledge creates internal conflict as he recognizes unsettling parallels to fictional narratives. Seeking emotional distance, Kotone applies his analytical grasp of BL story structures, vowing against falling in love or accepting submission. Yet his physical reactions persistently contradict this intellectual resolve, generating tension between mind and body.

The relationship with Nagi evolves beyond the physical as Kotone navigates the new world's social fabric, encountering other divine beasts and humans. His fudanshi background occasionally grants him insights into interpersonal dynamics, though real-world complexities consistently challenge his fiction-derived expectations. Ongoing interactions within this exclusively male society drive Kotone's character development, gradually reshaping his perspectives and fostering relationships extending beyond his initial connection to Nagi. This environment continuously tests his preconceptions and adaptability, reflecting a journey from theoretical relationship knowledge to direct, personal experience within an unfamiliar societal structure.