Kusari to Ai to Goraku o

Itsushi moves in with his boss, Kouji, after his mom marries Kouji's dad. Kouji also has a brother named Shinji. On the day he moves in, Koji calls him to his room at night and then takes him to a secret room. Itsushi is then raped and forced to become his pet. Will Itsushi ever find his freedom or give into being a pet?