I got started reading Tana French thanks to a recommendation from Peter Suderman on the Reason Roundtable podcast awhile back. Fair play to him, I've become a dedicated fan.
Her first six books were (more or less) a series, centered around the "Dublin Murder Squad", each one focusing on a different detective from that group. Each concentrating on the cops' psychological flaws/traumas, putting them through the psychic wringer. Her seventh book, The Witch Elm got away from the police at center stage, but the protagonist was (again) teetering on the brink of the basket.
Now, this one seems different at first. It's out of the city, set in a rural Ireland of sheep, bogs, hilly terrain, and colorful characters who like to tipple down at the local pub. This bucolic setting couldn't be farther from gritty, decadent Dublin.
Into this scene plops Cal, a retired Chicago cop, hoping to build a quiet life far from the ashes of his old one. (A bitter ex-wife, an estranged and slightly hostile grown daughter.) He's purchased an old farmhouse, a fixer upper. And so he sets to renovating…
The only problem being that he feels like he's being watched. And he is. But it's pretty easy for an ex-cop to get to the bottom of that little mystery: turns out it's a kid, Trey, from a nearby farm. They strike up an uneasy companionship, with Trey helping Cal with renovating. Trey's explanation for stalking Cal seems iffy, though. And it is: at the 17% point of the book (I got the Kindle version), it's revealed that Trey's big brother Brendan has gone missing, and Trey wants Cal to find out what happened to him.
And then things oh-so-gradually get darker from there, because people don't become saintly just because they're living in the countryside. Cal prides himself as having a "code", a set of morals that guided his behavior as a Chicago cop, and he maintains in Ireland. But as his investigation plays out, he finds that his code is inadequate to guide his path.