The series 'Yamitsuki Pheromone The Animation' centers on the high school student Saki, who suffers from a bizarre and potent condition: her body uncontrollably secretes an intoxicating pheromone whenever she gets aroused. This powerful scent drives any nearby male into a state of uncontrollable, primal lust, desperate to possess her sexually. The primary victim of this affliction is her own older brother, Kyouichi, who finds himself helpless against the overwhelming desire to fuck his sister. The narrative arc follows their escalating incestuous encounters. Initially, Kyouichi tries to resist, but Saki's dripping arousal and the potent pheromones saturate the air, turning him into a rutting beast. He relentlessly takes her, exploring every orifice with his hard cock. Scenes depict him fucking her raw in her bedroom, the classroom, and the nurse's office, often joined by other men like their teacher, who also fall prey to Saki's irresistible scent, resulting in debaucherous gangbangs where Saki is used as a communal fuck toy, her body covered in cum.