I just finished this book while sitting here at the Children's Desk. Wow.
It's a combination of ghost story, historical fiction and modern tale of grief and ptsd all rolled into one. This author did a serious amount of research on Boston history, Olmstead and the history of slavery.
Told from alternating points of view, Law and Katie tell their stories of their relationship with a historical house in the Emerald Necklace of Boston. Katie is haunted by ghosts of slaves and Law is fascinated by the architecture and torn by his parents' clashing opinions on what should be done with the property. At the same time, Katie is dealing with the devastating loss of her mother and Law is struggling with his race identity. It sounds like a lot, but Sarah Smith really makes it work.
It's chilling and detailed and even has a saitsfying end.