Lt. Eve Dallas is a capable New York detective married to Irish billionaire Roarke - a handsome devil with wild blue eyes (which are mentioned a few too many times in the book). Roarke recently purchased a dilapidated old Manhattan building that he's renovating. When workers tear into an old wall they're shocked to find two dead bodies. Before long a total of 12 bodies are found behind false walls, all of them teenage girls. Forensic examination and detective work reveal that the bodies were entombed about 15 years before, around the time the building was being used as a shelter for homeless/abused children.
Dr. Morris, the medical examiner, and Garnet DeWinter, a stylish forensic anthropologist, study the victims' bodies and reconstruct their faces. This reveals the girls' identities and cause of death.
Meanwhile Lt. Dallas and her partner (the always entertaining) Detective Delia Peabody interview Philadelphia and Nashville Jones, a brother and sister who ran the children's shelter, which was named "Sanctuary." Turns out the Jones' abandoned the old building about 15 years ago, when a generous donor gave them a new facility. The Jones' recognize photos of some of the dead girls and admit a few went 'missing' but - since homeless kids came and went all the time - they weren't especially worried at the time.
A lot of the book is taken up with Dallas and Peabody interviewing the parents/families/acquaintances of the newly identified missing girls. Some of the kids were rebellious runaways who'd argued with their parents and would have returned home. Other youngsters were escapees from horrible abusive families. The mistreated girls tended to become thieves and grifters, and one 12-year-old girl regularly traded blow jobs for beer and other perks.
The detectives also repeatedly interview the Jones', learning about their conservative religious upbringing, siblings (all of whom are named for cities), and desire to do good. Dallas and Peabody also investigate how the Jones' ran their shelters, and the regimen followed by the youngsters, who were NOT supposed to sneak out at night....but oh well.
Eventually a suspect emerges from the various interviews and clues, and Dallas pushes on to discover the truth.
The book has a LOT of philosophizing about brutish homes and troubled children, especially since both Dallas and Roarke had terrible childhoods. Though this is an important social issue there was too much of it and it slowed down the tale. There's also a lot of talk about Christmas and holiday parties and decorations. A great deal of this chit-chat seems like filler, meant to extend what's essentially a novella into a longer book. Moreover, there's a lot of romance between Dallas and Roarke...who seem to be the most 'in love' couple in the world. I didn't particularly enjoy these parts but I'm not a fan of romance novels.
All in all this was a mediocre mystery, enhanced by appearances from the usual array of the series' colorful (and oddly attired) characters. Fans of J.D. Robb's Eve Dallas series would probably enjoy this book but other readers maybe not so much.