From the moment of his birth, Keim is a cursed boy whose entire body is invaded by poison. Hated and despised, he suffers persecution even from his own father and sister. However, he eventually learns that the cause of the curse is the calamity sealed within himself, the Poison Queen. Risking his life, Keim confronts the Poison Queen and inherits her vicious abilities, awakening as the strongest being who can manipulate a wide variety of toxins――the Poison King! Keim unleashes his inherited talent for martial arts and decides to leave his hometown behind, living freely. However, during his journey, he inadvertently arouses the lust of a troubled beauty and a stunning woman he helps along the way with the aphrodisiac effects of his toxins…!?