In a world suddenly plagued by a bizarre and terrifying threat, humanity faces extinction at the hands of the Kiseichu—alien parasites that drain human energy and willpower by harvesting erotic and emotional vitality. Amidst this crisis, high school student Reto Enjou finds himself consumed by a burning desire to protect his childhood friend, Kirara Hoshino. Their once-close bond shattered after a
traumatic childhood encounter with a Kiseichu, causing Kirara to emotionally distance herself and grow fiercely apathetic toward romance and intimacy.Reto's desperate passion catches the attention of Gernum, a secret branch of the Japanese government dedicated to fighting the alien menace. Gernum operates under a unique premise: the Kiseichu draw power from human energy, meaning the only force capable of combating them is HxEROS—a specialized energy generated by intense human passion, desire, and libido. Reto is recruited as a "HxEROS" warrior, harnessing this lewd power to fight back. However, to unlock his maximum potential and transform into his battle suit, he must channel genuine erotic desire.Reto is soon partnered with an elite squad of high-school operatives: the aggressive and prideful Momoka Momozono, the wealthy and prim Sora Hojo, and the naive yet overly imaginative Mai Tenzai. Despite their initial reluctance and comedic clashes, the team bands together to fend off increasingly bizarre Kiseichu attacks across Tokyo. The dramatic turning point arrives when Kirara is unwillingly dragged into the conflict and awakens as a HxEROS warrior herself. To everyone's astonishment, Kirara possesses an unprecedented, world-class level of HxEROS energy, making her the ultimate weapon against the aliens.As the battles intensify, Reto and Kirara are forced to confront their unresolved past. Because Kirara’s immense power stems from suppressed passion, her participation in the team requires deep
emotional vulnerability. Together with their eccentric comrades, they must bridge the gap between their duty and their deepest desires, battling grotesque alien manifestations that mock human intimacy. Through high-stakes comedic peril and escalating romantic tension, Reto strives not only to save the world from the Kiseichu invasion, but also to melt the icy barrier around Kirara's heart, proving that genuine passion and affection are humanity's greatest and most powerful defenses.