Katori Shun, who is also an employee of the web production company "Cosmo Index" and is also a colleague of Nishijima Itsuka, has been unrequited for many years. As soon as he returned to Tokyo after a two-year transfer, Katori, who has a straight personality and will start approaching him again someday, is exactly the strongest boy in dog-type communication. In addition, during the two years he was away from Tokyo due to a job transfer, he grew rapidly into an adult man who naturally speaks words that would surprise women. Such Katori starts living "under one roof" with unique residents at the boarding house "Ginseiso". What kind of stories await there?
