My Classmate is Dads Wife (2007)

Junichi's father, Yoshiyuki is a professor of the university that Junichi goes to. Yoshiyuki has remained single since Junichi's mother died 10 years ago. One day, Junichi learns that his father is getting remarried; surprisingly his stepmother turns out to be Aya, the classmate he secretly admires. How will their relationship become? ...