Tohru has always been interested in his girlfriend's mother, Benihana. One day, he witnesses Benihana masturbating at her house. Unable to contain his excitement, Tohru sneaks up on Benihana when she's not looking. Benihana is confused, but is unable to resist the pleasure she hasn't felt in a long time and accepts Tohru. Since then, they have been having a relationship, hiding it from their daughter...