When Faith is summoned from the baby farm in suburban London, where she's grown up, to serve as a companion to her cousin, Margaret is stunned. The family home Rockglass Manor is in Mayfair, an elegant part of London.

Faith is sure her life will vastly improve. Yet, when she reaches Rockglass Manor, no one seems to be waiting for her, other than the cook and the housekeeper. Her cousin Margaret is trouble, and Faith finds herself rocketed into a situation that she doesn't understand, at all.

She finds a stone in a nest outside her bedroom window and learns quickly that if she lets it, it will give her guidance. Meanwhile, her aunt, Margaret's mother, has lost her sanity, and her uncle Lord Rockglass is a mysterious figure that she seldom sees.

There are other secrets in the house that baffle her, such as the presence of Enid, a younger girl who lurks in the kitchen, but does not seem to be a servant and Margaret's habit of disappearing at all hours of the day or night.

Faith does her best to fit in and be helpful, as she prefers Rockglass Manor to the Brigitts' baby farm in Stockwell. She is quite surprised when her friend Jack arrives and becomes a fixture in her new life.

As her days in London progress, life becomes stranger and stranger. She is forced to recognize the identity of her mother and, even worse, her father. With the help of Jack's employer, Mr. Sylvester, she learns how to use her stone, which has the formal name of The Robin's Egg Stone. She also finds there are other stone bearers, and that they can work together to right age-old wrongs.

This is the first book in the trilogy.