Sayuri Kirishima serves as the responsible student council president while attending school, characterized by her violet hair and red eyes. She falls prey to the manipulative schemes of Murakoshi, who employs hypnosis to control others. Despite her inherent honesty and ethical nature, she underestimates his deceitful tactics, leading her, her sister Manami, and several classmates into his hypnosis trap. Seeking to protect her peers, Sayuri attempts a selfless sacrifice, offering herself in exchange for their freedom. This effort fails; Murakoshi exploits her sister and the other students regardless. Her story concludes tragically, with both sisters remaining under Murakoshi's control, trapped in their manipulated state.