It's Christmastime in 1905 New York City, and for once, Molly Murphy Sullivan is looking forward to the approaching holidays. She has a family of her own now: she and Daniel have a baby son and twelve-year-old Bridie is living with them as their ward. As Molly and the children listen to carolers in the street, they hear a lovely voice, the voice of an angel, and see a beggar girl huddled in a doorway, singing "Away in a Manger." Bridie is touched by the girl's ragged clothes and wants to help her out if they can. They give her a quarter, only to watch a bigger boy take it from her. But Molly discovers the boy is the girl's older brother. They've come from England and their mother has disappeared, and they're living with an aunt who mistreats them terribly.
Molly quickly realizes that these children are not the usual city waifs. They are well-spoken and clearly used to better things. So who are they? And what's happened to their mother? As Molly looks for a way to help the children and for the answers to these questions, she gets drawn into an investigation that will take her up to the highest levels of New York society.