Rio Nogami prefers to keep his sexuality a secret, so when he runs into the school's freedom child Etsushi at a gay club, it comes as a surprise to both of them. Rio is a cool and collected member of the archery club and while he is confident with his own sexuality, he is still young and naive about sex and romance. On the other hand, Etsushi is a free bird in all senses, waltzing into class when he pleases and going along with other men's desires. So, to keep things in order at school, Etsushi and Rio come up with a few rules. But... aren't rules meant to be broken?... (Source: Torico)

Rule Sono Ichi was published digitally in English as Rule Number One by Renta! and as Rule No.1 by Torico.