After the death of his father, Yuichi goes to live with his father's ex-wife, Yukiko. Yuichi doesn't know much about Yukiko until he finds a video tape showing his father having sex with her.
Yukiko has a daughter Mika; from a picture she saw of Yuichi she already has a crush on him. It quickly grows into obsession. She wants to be with him. All this confuses Yuichi. What will he do?