Watakushi to Kowareta Kyuuketsu Ki

As a child, Itsuki finds comfort in a captivating boy who lives alone in a distant mountain castle while her parents leave her with indifferent step-siblings. One day, the boy disappears without a trace. Years later, burdened with responsibilities her parents have abandoned, Itsuki longs for someone to take care of her. The boy from her past suddenly returns, saving her from a life-threatening moment—but he seems distant, and his actions are unfamiliar. Itsuki begins to wonder who he is now, what secrets he keeps, and what he wants from her.