"Ayakashi Triangle" centers around Matsuri Kazamaki, a young exorcist tasked with protecting humanity from malevolent spirits known as ayakashi. Matsuri’s childhood friend, Suzu Kanade, possesses a rare ability to attract ayakashi, making her a constant target. To safeguard Suzu, Matsuri dedicates himself to exorcising the spirits that threaten her. However, during a confrontation with a powerful ayakashi named Shirogane, Matsuri’s life takes an unexpected turn. Shirogane curses him, transforming his body into that of a girl. This curse complicates Matsuri’s life, as he must now navigate his new identity while continuing his duties as an exorcist.

The narrative explores Matsuri’s struggle to adapt to his transformed body, balancing his responsibilities as an exorcist with the challenges of his altered physical state. Suzu remains a central figure, her bond with Matsuri deepening as they face various supernatural threats together. The series delves into themes of identity, loyalty, and the complexities of human relationships, all set against a backdrop of supernatural conflict. The dynamic between Matsuri and Suzu evolves as they confront both external dangers and internal emotional struggles, with Matsuri’s curse serving as a catalyst for growth and self-discovery.

The story also introduces a range of supporting characters, including other exorcists and ayakashi, each contributing to the overarching plot. The interplay between human and supernatural elements drives the narrative forward, with battles against ayakashi providing action and tension. The series maintains a balance between lighthearted moments and more serious themes, creating a multifaceted exploration of its characters and their world. Through its blend of supernatural action, humor, and emotional depth, "Ayakashi Triangle" presents a story that intertwines personal growth with the ongoing battle between humans and ayakashi.