The Janus Stone — Elly Griffiths

It's only been a few months since forensic archeologist Ruth Galloway found herself entangled in a missing-child case, barely escaping with her life. But when constructions workers demolishing a large old mansion to make way for a new development uncover the bones of a child beneath a doorway -- minus its skull -- Ruth is once again called upon to investigate. Is it a Roman-era ritual sacrifice, or is the killer closer at hand?

When carbon dating proves that the child's bones predate the home and relate to a time when the house was privately owned, Ruth is drawn more deeply into the case. But as spring turns into summer, it becomes clear that someone is trying very hard to put her off the trail by frightening her, and her unborn child, half to death.