Ichika's homeroom teacher, Riku, was introduced to her mother as her new boyfriend. Ichika has always had a boyfriend, but she has always loved Riku. Ichika kisses a drunk Riku at her girlfriend's home. Riku feels drawn to Ichi, the daughter of his girlfriend, and even though he thinks he shouldn't mess with Ichi, who is her student. And Ichika, who wanted Riku as her own,