Shirafuji is an ordinary librarian. There are three additional "sexes" in the world, Alpha, Omega and Beta. Alphas are more dominant and can secrete some pheromones, Shirafuji is an alpha and his scent resembles wild berries or something light. He is in a relationship with a strict office worker Tsukasa, who is an omega and can have children, but this does not make him any less strict. His scent resembles a peach or something sunny. Outwardly, it may seem that they are just acquaintances