Three 20-something sisters, Ayame, Kaede and Sumomo, have just about had it with men. Ayame walked in on her husband's infidelity, only to have him leave her for the other woman. Kaede had a crush on a colleague, only to find out he was sleeping with his high school students and keeping a porn stash of their pictures. Sumomo just can't seem to find a guy that's good enough for her. Their lives change the day their little brother Mikio comes to Tokyo to live with them, just after high school graduation. They all become immediately infatuated and aggressively sexual with him. Mikio wishes they would just act like normal sisters, especially since they seem hellbent on ruining his budding relationship with a cute girl named Midori. Will Mikio be able to have a real relationship with a girl, or will his three housemates have their way with him?