Wakamatsu Masato lives with his step-sister, Miyuki, with whom he shares no blood relation. Their father is constantly working overseas, leaving the two of them to live alone in Tokyo. Miyuki is cute, kind, sensitive, and very popular with the guys around Masato. Masato has a girlfriend at school named Kajima Miyuki, who is pretty and gentle—the ideal dream of every high school boy. It took years for Masato and his sister to realize whom they love and care for the most.