Hiroshi has been dating his girlfriend for about half a year. Her mother, Ryo, is a beautiful, composed, and hardworking single mother who raised her daughter alone. Though Hiroshi intends to treat his girlfriend as a lover and Ryo as a parental figure, his relationship with both women has deepened in unexpected ways. Whenever they're alone together, he can't suppress his desire—his body reacts instinctively. They both know it's wrong, but the connection they share is now impossible to stop. Amid this secret affair, the emotional turmoil between the daughter and her mother continues to grow.