Thirteen-year-old Rose Campbell never knew her mother, and the death of her father leaves her reeling and hopelessly lonely. She's sent to live with her maiden great aunts, the matriarchs of her father's wealthy Boston family who she's never met. The elderly women's quiet household suits Rose's mourning, but the arrival of her appointed guardian, Uncle Alec, challenges the status quo.

With Alec as her guide, Rose is properly introduced to the other residents of "Aunt-Hill," including Alec's four sisters and their sons. Having so many relations overwhelms Rose at first. Her dour Aunt Myra convinces her she has a fragile constitution while fashionable Aunt Clara turns Rose's head with stylish clothes. And the collective energy of male cousins ranging from age six to sixteen is more than she knows how to handle. But Uncle Alec's steady commitment to seeing Rose flourish helps her find her footing and grow to love her eccentric family. She even "adopts" Great Aunt Plenty and Peace's housemaid, Phebe, as her sister.

Surrounded by people who love her, Rose slowly but surely goes from sickly and timid to healthy, active, and bold as she learns to keep her father's memory close while setting a course for a happy future.