The Nanny by Ruth Heald
I absolutely loved this one. A woman and her husband decide that taking in a lodger is the best way to ease the strain on their finances. It's an idea that they've discussed and decided against before, but they're running out of choices and the young woman who comes to look at the room seems absolutely perfect. It has to be a coincidence that she looks like someone Hayley had spent twenty years trying to forget. Not even Hayley's husband knows the story of "Bangkok's Killer Nanny"...but suddenly a lot of people are curious about her gap years and what happened in Thailand twenty years ago.
The book alternates between past and present, always from Hayley's point of view. The story gradually unfolds, finally revealing what happened to baby Chloe and what's going on now, but the pace never drags and I never felt like the author was deliberately stretching things out or hiding things from the reader. It was an engrossing read that has me wanting to track down the author's earlier books as soon as I can.
Disclosure -- The publisher provided me with an advance review copy. This post contains affiliate links.