In the district of Monzen-Nakacho of Koutou in Tokyo, three sisters live in one house. The Watanuki sisters had a life of hardships, a life without a mother, who died in their early childhood and now without a father, who died just a year ago. Now alone and becoming the inheritors of the Watanuki house, the sisters have to endure several situations in their everyday lives; whether those are happy, sad or special, they will test the sisters' bonds as a family.