Des:The older sister, Yuu, is strong-willed and a bit selfish, and the younger sister, Chiharu, is quiet and doesnt get pushed easily. The two were having tea in the living room and complaining about each others boyfriends. When she hears from Chiharu that her boyfriend has too much sex and is in trouble, Yuu becomes a little jealous, and her boyfriend becomes interested in her. So, Yuu asked Chiharu, ``Shall we exchange boyfriends?