In this world, everyone is assigned an animal and a rank (ABO) since birth. The animal a person is assigned to is the animal they can turn into. The ranks are Alpha, Beta, and Omega.

Ren's animal is an Omega bunny, which he is ashamed of since he is rather weak and low ranked.

Today was a special festival, which takes place once a year. It's a "mate finding" festival for lone Omega's to find an alpha/beta mate. The only rules were no violence and that everyone has to be in their animal bodies.