After being reborn, the former Demon King Ryusei Narukami is now a total shut-in NEET. But his quiet second life is shattered when Meteor Hanaori—the hero who once killed him—shows up as an ordinary high school girl. Determined to turn things around, Ryusei becomes a teacher, only to land a job at her school. Their explosive reunion reopens old wounds—and unexpectedly ignites a new romance.