Cal Hooper is a retired Chicago police detective who is recently divorced. Those two major life changes have prompted him to make a third. He's bought a rundown farmhouse (from an online posting) in a rural part of Ireland and is determined to live there bothering no one and bothered by none. His first weeks in his new home live up to that ideal. He heads to the local village when he needs supplies or to stop in the pub for a drink, but otherwise is keeping to himself. His solitude is disrupted one day when he realizes someone is watching him. When Cal catches the watcher he finds it's a young kid named Trey. Though initially reluctant to let anyone into his new quiet life, Cal can sense that Trey wants something and is willing to be patient in finding out what that is.
The thing is for Cal to investigate the disappearance of Trey's older brother Brendan who left the house one day and never returned. Cal does start to ask questions but everyone in the village is sure that Brendan, whose family is poor and chaotic, simply picked up stakes and moved to Dublin. Trey is certain this isn't the case and Cal cannot resist doing a little bit more digging. What he discovers is that he hasn't left all the darkness behind in Chicago.
This is a slow-paced character study that will take you a bit to settle into - and that's good. Tana French is writing about a rural Ireland that isn't all cozy and twee. It's a place where poverty and lack of opportunity drives out many of the young people and where drugs and crime can still get a toehold. The Searcher is ostensibly about the disappearance of Brendan, but it's also about what desperation can do to people and delves into the lengths they'll go to when necessary.