After a major earthquake, an opportunity arises that changes the destinies of two young girls. Yui, a 17-year-old runaway, and 8-year-old Hiyori (a mute orphan) adopt the identities of the granddaughters of an elderly lady named Kiwa Yamana who offered them a helping hand. From that day on, the three of them began a wonderful life together in a mysterious old house called "Mayoiga".