The central character is Joanne, who suffers a great loss when she is six. We get to pick up on her life thirty years later, where we find she has become a doctor, is married and has a baby son she adores - and may be threatened by the same man who destroyed her family 30 years before. Joanne is kind and thoughtful and just possibly stronger than she looks.
On another track is Louise, a police detective particularly obsessed by cases of violence against women. She too is married, to an understanding and unflappable doctor, but she feels the need to test their bond again and again. She is prickly and aggressive.
Jackson Brodie is a former detective (also former police detective and former military guy), newly married yet on a trip to see a young son whose mother insists is not Jackson's. By a stroke of luck, Brodie has inherited big bucks so does not have to work, but he does not feel he really earned it so does not flaunt it. Brodie was central in Case Histories and One Good Turn, Atkinson's previous two novels, as well. His trip is more adventurous - and dangerous -than he would like.
Primary driving force, though, is Reggie. Reggie is a sixteen-year-old girl ("with a boy's name") who takes care of Joanne's baby and dog when the doctor is at work. Having struggled through quite a life already, Reggie is remarkably open to affection and is tough and resilient. She is also loyal and determined. It is Reggie who really brings everyone together. Reggie is also quite the little scholar, learning primarily on her own. Atkinson nails the teenage speech, which I found highly entertaining.
Joanne disappears one day and Reggie seems to be the only one who thinks there is something suspicious about the story her husband offers. The baby is with her but not the dog. And not a few other things that Reggie in particular insists would have been with her.
Beyond the suspense of the story there are the characters. All fully-formed persons, we get to see how they make decisions, good and bad, and act intelligently or not. We also get a great sense of place and custom, without being overwhelmed by it. The book is enjoyable for its quiet humor and believable characters, beautifully drawn, so fun to watch.