One day, the Hanabishi and Hidaka parents were preparing for a long term overseas business trip together. Kouki ended up living together with the four sisters. And one of them is promised to him as a fiance. But who should he choose? The third wife material: The second born daughter, Momone: She absolutely adores Kouki, and does nothing but spoil him. The fourth wife material: The youngest daughter, Anzu: She has problems showing her real feelings, and appears more bratty.