Livy Jackson and her husband, Will, live the quiet, suburban life in Exeter with their two children, Hannah and Zac. After a rough patch, both hope for a fresh start on their marriage. Livy is still plagued by Will’s infidelity six years previously. She’s has had years of apologies from Will, yet none of them have has turned back the clock. Now she must contend with an anxious and overly-burdened Will, who seems to be overcompensating after fourteen years of marriage. Livy has tried to forgive and forget, but over the past six years the memory of the affair has retained its power to corrode her trust.

Life for Livy in Exeter is full of heartache and old memories, especially surrounding death of her sister, Kara, who was viciously murdered one cold February night in her first year at university. As Kara was walking along the canal back to her student housing, someone raped her with a knife then stabbed her in the stomach. Her killer was never found. Julia’s demise was a terrible violation, “a gash” that tore right through the mundane existence of Livy and her parents’ average, suburban lives. Livy has never been able to recover from that night. Only Livy’s best friend, Julia, was able to get her through the pain.

When Livy shows up at Julia’s flat with Hannah and Zac in tow, she’s horrified to discover Julia’s lifeless body on the sofa. According to the post-mortem report, Julia killed herself from a lethal dose of Nembutal. The sudden death of her best friend puts everything in perspective, especially the lingering doubts in Livy’s mind about Will’s infidelity. Livy is convinced there’s no way Julia could have killed herself. Julia was happy and full of life, not secretive and depressed. She initially tries to tell Will, but he’s too preoccupied and exhausted from work. At odds with Julia’s parents and with the police findings and against the advice of Julia’s family, Livy begins to investigate her friend’s death herself, surreptitiously entering into Julia’s flat to look for evidence that she didn’t kill herself.

Here Livy finds a clue that leads her to a singles bar in Torquay called Aces High and into the orbit of Julia’s handsome boyfriend, Damian, who tells Livy that Julia felt guilty that she hadn’t protected Kara that night. Apparently, Julia carried her guilt with her all the time and never forgave herself for not being there for Kara. Damian also tells Livy that the night Julia died, she needed to talk to her. She was going to tell Livy that she knew who “he was, and that she’d found him.”

The energy of the novel is built in the connections between Julia, Kara, and Livy’s pasts as McKenzie intersperses her chapters with the dark heart of a serial killer whose narrative begins on the night of Kara’s murder by the towpath. It’s a heinous crime from a killer who becomes even more emboldened as the years progress. Over the years, the police have had few leads in a series of brutal murders and are unable to reconcile any past connection to Kara. Livy enlists the help of handsome Damian, the two blindly groping forward, increasingly convinced that Julia was murdered by a psychopath whose constrained, ordinary life masks a whole series of sick desires and evil actions.

McKenzie does an adequate job of adding her voice to the crowded pack of the mystery/murder genre. While she’s not the most eloquent of writers, she knows how to create tension and excitement even when she relies on clichéd themes (the fractured, dysfunctional marriage, the handsome boyfriend who in Livy’s eyes becomes a suspect, the difficult dynamic between mother and daughter). We know from the outset that Livy and Will have had marital issues, but the anger and bitterness is allowed to fester--that is, until Julia’s death makes it all explode. Similarly, Hannah’s rebellious teenage years are also explored as the relationship between her mother is damaged yet again. Livy is scared of her daughter’s hurtful rejection and scared of her own turbulent feelings. Also, the killer’s macabre journey towards violence are hinted at in stages, which further perpetuates the notion that he/she is someone that Livy knows and trusts.

McKenzie’s talent is that she can keep us guessing, although the prime suspect sometimes becomes decoration to Livy’s complicated investigation. McKenzie also throws in a heap of colorful, complex secondary characters who may or may not be suspects: Julia’s sleazy, self-serving brother, Robbie; her bitter, angry mother, Joanie, who cares more for Julia’s money than the memory of her daughter; and the phony manager of Honey Hearts, the agency for unfaithful husbands. She probably holds a vital clue to Julia’s murderer in the draws and files of her office.

Although the novel often reads like a B-grade TV thriller and has a plot riddled with over-the-top melodrama (particularly the last pivotal scene where Livy confronts the killer), McKenzie presents a compelling thriller that centers around the agony of betrayal along with the price of marriage, friendship, and trust.