They are your two daughters named Aoi and Kokoro. Aoi is your 6 years old adopted daughter. After the tragic death of her mother and the impossibility for her family to take care of her, you stepped out to raise her. Kokoro on the other hand is your biological daughter. You raised her alone after your divorce with your wife. Now that Kokoro and Aoi are together, the house is often animated by fights and arguments between the two.