Cal Hooper thought a fixer-upper in a bucolic Irish village would be the perfect escape. After 25 years in the Chicago police force and a bruising divorce, he just wants to build a new life in a pretty spot with a good pub where nothing much happens. But when a local kid whose brother has gone missing arm-twists him into investigating, Cal uncovers layers of darkness beneath his picturesque retreat, and starts to realize that even small towns shelter dangerous secrets.

Toby is a happy-go-lucky charmer who has dodged a scrape at work and is celebrating with friends when the night takes a turn that will change his life --- he surprises two burglars who beat him and leave him for dead. Struggling to recover from his injuries, beginning to understand that he might never be the same man again, he takes refuge at his family's ancestral home to care for his dying uncle Hugo. Then a skull is found in the trunk of an elm tree in the garden --- and as detectives close in, Toby is forced to face the possibility that his past may not be what he has always believed.

Being on the Murder squad is nothing like Detective Antoinette Conway dreamed it would be. Her partner, Stephen Moran, is the only person who seems glad she’s there. Their new case looks like yet another by-the-numbers lovers’ quarrel gone bad. Aislinn Murray is dead in her living room, next to a table set for a romantic dinner. There’s nothing unusual about her --- except that Antoinette has seen her somewhere before. Other detectives are trying to push Antoinette and Steve into arresting Aislinn’s boyfriend. Is this case another step in the campaign to force her off the squad, or are there darker currents flowing beneath its polished surface?

Detective Stephen Moran has been waiting for his chance to join Dublin’s Murder Squad when 16-year-old Holly Mackey arrives in his office with a photo of a popular boy whose body was found at a girls’ boarding school a year earlier. The photo had been posted at “The Secret Place,” the school’s anonymous gossip board, and the caption says “I KNOW WHO KILLED HIM.” Stephen joins with Detective Antoinette Conway to reopen the case. The private underworld of teenage girls turns out to be more mysterious and more dangerous than the detectives imagined.

Mick “Scorcher” Kennedy plays by the book and plays hard, which is what puts the biggest case of the year into his hands. On one of the half-built, half-abandoned “luxury” developments that litter Ireland, Patrick Spain and his two young children are dead. But Broken Harbor holds memories for Scorcher, and working this case could resurrect something he thought he had tightly under control.