Wakamatsu Masato lives with his step-sister, Miyuki, whom he does not have blood relationship with. Their father is always working overseas and left the two of them living by themselves in Tokyo. Miyuki is cute, nice, sensitive and very popular among guys around Masato. Masato has a girlfriend at school whose name is 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 the most.

(Source: The Ultimate Manga Guide)