START-419 A nagging high school teacher who missed her chance to get married is a total pervert whose hobby is exposing herself in class. When her students discover her hobby, she is forced to mate with them like monkeys, and is reminded of her instincts as a female. Yui Mahiro

Ms. Yui is a tomboyish teacher who always wears tracksuits and nags at the dumb male students. Her students laugh at her behind her back, saying things like, "She definitely doesn't have a boyfriend," "She's probably a virgin," and "She's completely missed her chance to get married." However, her true nature is that she has a stronger sex drive than most, and she is a total pervert who enjoys exposing herself and masturbating in the school during class or after school when no one is around.