RBD-769 The Day My Big Sister Became Completely Mine Yu Konishi

Marriage was decided and Yu's work as an office worker was going well, but the only cause for anxiety was that his younger brother, Kazu, suddenly refused to go to school and shut himself up in his room. When Kazu finds out about his sister's marriage, he goes berserk...he violently assaults her mother and commits forbidden acts against her sister...