Robin Sena, a fifteen-year-old craft user raised by the Church in Italy, arrives in Japan to join STN-J, the local branch of the secret organization Solomon that tracks people whose latent witch powers awaken. Where other branches kill, STN-J tries to capture witches alive to study how their abilities surface. Robin works her first cases alongside the team's hunters using her pyrokinesis, while the reasons behind her transfer and the truth of her own power stay just out of reach.