In a world where demons known as Kirionira breach the human realm through dreams, humanity relies on hunters fueled by their libido to fend off these otherworldly threats. Riku Yoichi, a descendant of a prestigious line of hunters, possesses exceptional sexual energy that sets him apart as a skilled protector. After leaving his hometown post-middle school to vanquish the Kirionira menace, Yoichi successfully eliminates their king, securing peace at a cost - the loss of his sexual prowess. Upon his return, he discovers the demon incursion persists, yet his diminished libido renders him incapable of combat. Desperate, he seeks the aid of his childhood friend Namba Midori and her peers to reignite his passion, only to face rejection as they shun his plea for assistance.