Like “The Little Engine That Could,” this mystery tries its best to reach a level of authority but fails to support its plot. The premise of the drama--the sudden “suicide” of Livy Jackson’s best friend, Julia Dryden--so unsettles Jackson that she finds it impossible to accept the death as intentional, regardless of the official finding. Still mistrustful of husband Will’s fidelity after a dalliance six years prior, Livy has grown accustomed to asking Julia for advice, sorely missing her friend’s sense of humor and cynical perspective on life’s ironies and miscalculations. Julia was originally Livy’s sister’s best friend, but when Kara was murdered eighteen years ago (the case yet unsolved) the two became confidantes.

Unfortunately, both of Livy’s children, Zack and Hannah, were present when the body was discovered. The younger Zack takes it in stride, while twelve-year-old Hannah is less able to deal with the death. In the throes of adolescent rebellion, Hannah’s relationship with her mother grows more fractious without Julia’s assistance, Livy too obsessed with proving it a murder to attend to her daughter’s emotional needs. Livy’s home is in an uproar, her painstakingly rebuilt marriage at risk with rumors of another tryst between Will and his work colleague Catrina, arguments with Hannah more heated, though it doesn’t help that Livy reacts to Hannah’s challenges as if they are contemporaries, not mother and daughter.

Livy finds a mysterious entry in Julia’s diary, an appointment set for two weeks after her death. The same night Livy attempts to replace Julia at the place and time listed, she also meets a man who claims to be Julia’s secret boyfriend, Damian. Ironically, Damian harbors the same suspicions as Livy--that Julia’s death is, in fact, a murder. The oddities of behavior and plot threads--notably Julia’s family’s resistance to accepting Livy’s murder theory, Hannah’s increasingly worrisome behavior and Livy’s unquestioning acceptance of Damian as an accomplice in solving Julia’s “murder”--are complicated by inserted chapters in the voice of a serial killer who gleefully reports his progress from torturing animals to human victims, including Livy’s sister, Kara. Apparently, his identity will surface at some point, lest the reader fear that Livy is manufacturing the drama.

There are an abundance of red herrings in service to Livy’s suspicions, some even remotely believable, but the way that Livy tackles her problems, her absolute lack of logic, doubt or trepidation, feeds inaccurate assumptions and alienate her closest ally: her husband, Will, who eventually becomes the object of her suspicion as Julia’s killer as well. While the mystery illustrates how overwhelming resistance to facts/evidence can undermine a woman’s ability to reason and exercise self-protective measures when conducting a potentially dangerous investigation into the behavior of others, Livy’s impulsive actions undermine her credibility as a protagonist. She steps blindly into compromising situations only to be shocked at the consequences of such missteps.

Begun with Kara’s murder eighteen years earlier, a serial killer now intruding into his victim’s life to inflict more damage, this tale has potential but is mostly squandered by Livy’s inept investigation into Julia’s death with no tangible evidence to support her theories. Some may be satisfied with the actions of this character--might actually find her believable--but her propensity for bumbling through relationships until she stumbles on the truth is more a product of happenstance and the author’s imagination than a well-planned plot. McKenzie redeems herself near the end when the action accelerates toward a revelatory climax, finally tying up loose ends, but I had to work too hard to get there.