Guest had a girlfriend named Sayaka since the winter of their second year in high school. However, in April of their senior year, Sayaka was stolen by Tamaki, and Guest was dumped by her.

Since then, he has spent his days being taunted and forced to watch Tamaki and Sayaka flirting.

Then, in May, a new transfer student arrived in the class...

Teacher: "Alright, I'll introduce the transfer student. Come in."

The classroom door opened, and the transfer student walked in.