Building a multi-pronged narrative around a serial killer, the murder of a seemingly perfect middle-class mother, plus the domestic and professional trials of her heroine, Frieda Klein, French plunges the reader into an exploration of appearances and instinct. Frieda—driven by irrationality and a paranoid instinct in the wake of her own trauma—embarks on an inexplicable search for a girl she has never known, while DCI Malcolm Karlsson and DC Yvette Long are called to a late-Victorian semi-detached in Chalk Farm, a couple of streets away from the noise of Camden Lock.

Here lies the shattered body of Ruth Lennox, “splayed under the lights as if she were on stage.” The scene is grisly: Ruth’s head has been smashed in, the left side sticky with liquid, and bits of bone and blood are splayed over the walls, turning this tranquil, middle-class living room into an abattoir. Ruth’s husband, Russell, and her three kids—Dora, Ted and Judith—remain in a state of shock. Only Ruth’s meddling sister gives the scene a sense of calm and order, having gathered to help and sympathize, perhaps to “warm herself in the terrible glow of death.”

Dark, forbidden secrets lie beneath the calm veneer of respectable London where lives at first seem anchored in the texture of a genteel daily existence. The photograph of the gleaming, happy Lennox family is far from the reality of the crime scene: a dead woman lying a few feet away and a family grieving in a crime that Karlsson thinks is a burglary committed by local petty criminal Bill Hunt during which he “redecorated the room with Ruth’s blood in a kind of love.” At first, Frieda has little to do with the investigation. Her methods are viewed by the London Police Department (and particularly by her nemesis, Hal Bradshaw) as too unorthodox and instinctive. Frieda’s actions are obsessive and self-destructive, and have led to her dismissal during the last round of cuts. She’s also been accused of stepping on others’ toes and has made Bradshaw look stupid and amateurish in the eyes of the Constabulary’s autocratic brass.

Driven intellectually and also challenged by her instincts, Frieda is never one to admit defeat—not by Dean Reeve, a child abductor and a murderer who has become her stalker and her quarry, nor by Bradshaw, who sets Frieda up with a phony patient in an attempt to sabotage her professional reputation. Initially designed to make Frieda look foolish and incompetent, Bradshaw’s scheme instead backfires, plunging Frieda into a search for a girl called Lila who went missing several months previously.

French spends an equal amount of time going back and forth between Karlsson’s hunt for Ruth’s killer and Frieda’s daily life as concerned sister to her drunken, irresponsible sibling Olivia, de-facto mother to niece Chloe, and an impromptu grief counselor to the Lennox kids—particularly wasted, sunken-cheeked Ted, who lands on her doorstep trailing behind a concerned Chloe. Initially the arrival of the kids seem like a refuge from the violent mess of the world, a way of balancing Frieda’s creeping involvement with the police and her unshakable preoccupation with the shadowy word of Lila, and of course Dean Reeve who always seems to be keeping watch. (Here French inserts a silly subplot involving Josef, Frieda’s builder friend from the Ukraine, who has entered her life in an unlikely way and wants to give her the gift of remodeling her bathroom). This constant noise only adds to Frieda’s anxiety as she pines for her lover Sandy, who remains in New York, out of reach.

Like the other books in the series, the turbulent London provides a frenetic backdrop to Ruth Lennox’s murder, her demise eventually viewed by Karlsson and Yvette Long as affiliated with some long shadow, perhaps a family member, cast by a dark secret from the past. Adding to this state of perpetual unrest is a side story of journalist Jim Fearby, who is convinced that convicted murderer George Conlon was wrongly sentenced for killing a teenage girl. With Conlon about to be released, Jim embarks on the mission to find a serial killer, the trail taking him to several broken, embittered mothers of missing girls, their long-buried memories and sad confessionals showing just how much the police botched their investigations of the cases. Fearby’s well-plotted and exacting suspicions about Conlon’s innocence are vindicated when he begins to discover the hard truths about Hazel Barton and the final moments of the other victims.

While many of the side stories and secondary characters sometimes convolute the novel and don't feel quite as essential to the main plot, they are important for providing context and depth to French’s examination of the relationships between husbands and wives, mothers and sons, and the complexities of clandestine sexual passion. As Ruth Lennox’s past proves, real secrets aren’t found in objects, in schedules, in underwear draws, or deleted texts, but are lodged far deeper, perhaps unavailable even to ourselves.

In a chaotic blend of evil that breathes and pulses with gritty reality, Frieda anchors this story. Her steely demeanor only occasionally betrays vulnerability and a serious desire not just to catch a serial killer, but to provide a certain justice for his innocent victims.