Broken Harbor is the fourth installment in Tana French’s fantastic Dublin Murder Squad series. Each of her the novels feature a different member of the squad, usually a character introduced in a previous work. French expertly pairs each fully-formed character with a complementary storyline and appropriate tone. Broken Harbor highlights Mick “Scorcher” Kennedy, who was introduced as a minor character and antagonist of sorts in the previous book: A Faithful Place. Kennedy has an excellent track record with the squad and is known for his diligence and strict adherence to procedure. When a triple murder gets called in, his superior offers him a chance to head up the high-profile investigation. During their conversation it is intimated that there was a prior case that was uncharacteristically problematic for Scorcher. He needs to redeem himself by quickly resolving this one to retain his reputation. He also is obliged to act as a mentor to his rookie partner, Richie. Richie is rough around the edges, but eager to prove himself. Meanwhile, Kennedy’s mentally-ill younger sister returns and caring for her is a potential distraction and a conflict of duty. The triple homicide brings Scorcher back to a familiar location that has some strong emotional attachment for him and his family. Kennedy’s own complicated backstory is carefully unfolded as he investigates the murder of the young family. He and his new partner seem well suited to each other, and he begins to feel a guarded respect for the younger officer. Scorcher’s past has alienated and hardened him, but he begrudgingly suspects that he might eventually accept Richie as a permanent partner or friend. Broken Harbor, like all of French’s novels, is exquisitely paced and well-written. It is a thrilling mystery with many unexpected turns that also manages to address some deeper themes as well. The need for keeping up appearances, the power of shame and the nebulous boundaries between right/wrong weave into the narrative. As a staunch believer in the rules, Kennedy prefers clear-cut answers when “the world’s vast hissing tangle of shadows burns away, all its treacherous grays are honed to the stark purity of a bare blade, two-edged: cause and effect, good and evil.” Unfortunately, he discovers that circumstances are often far more complicated and may not be so easily defined. This case will challenge Scorcher’s core beliefs and cause him to question all the rules he has come to rely on. Broken Harbor can be read as a stand-alone novel, but mystery fans would benefit from starting the series from the beginning.