Wakamatsu Masato has had a crush with his classmate, Kajima Miyuki, who is the idol at their high school. Kajima begins to develop feelings for Masato during their summer break.

Near the end of their break, Masato meets a pretty girl on the beach. Later on, he finds out that she is his non-blood related step-sister, Wakamatsu Miyuki, whom he hasn't seen since he was little.

Both girls ironically have the same name, Miyuki, and both fall in love with Masato. Now Masato must choose between the two. Who will he choose?