Whether a grizzled ex-FBI agent, a cunning private eye, or a new breed of truth seeker, Brigid Quinn--Masterman’s plucky fifty-eight-year-old protagonist--seeks to peel away the layers of a serpentine investigation to arrive at a stunning revelation. Living in Tucson and just recently married to Carlo, a Catholic priest turned philosophy professor, Brigid is relieved that she’s still fit enough after working for years as an undercover agent: “I was tough. I may be small and have prematurely white hair, but I’m as psychologically and physically fit as you can be at my age.”

Brigid is lucky enough to be able to share her deepest, darkest confidences with best friend, Mallory, who likes to drink wine and shop and flirt (occasionally with Carlo). After volunteering at a local abused women’s support group, Brigid looks forward to a glass of red wine and a hot bath with some “Tired Old Ass Soak,” but not before she gets the sad news that her sister-in-law Marylin has just died. Suddenly it’s time to keep the promise she’d made to Marylin all those years ago: that Marylyn’s daughter, Gemma-Kate, stay with her and Carlo for a few months so that she can qualify for in-state tuition at the University of Arizona.

Unused to children and teenagers, Brigid is initially hesitant, reluctant to let an outsider into her marriage and do anything that might upset the delicate equilibrium. Carlo, on the other hand, jumps at the chance. Soon Gemma-Kate is kicking the family up a notch with her youth and excitement about her new surroundings. It looks like Brigid has landed in a good place, with a congenial niece and with Carlos, a good mentor-type. However, when Gemma-Kate poisons one of Brigid’s beloved pugs with a Colorado River Toad, as might be expected, Brigid begins to harbor ambiguous feelings toward the girl whom she seeks to share such an intimate bond.

From the outset, Masterman establishes a stinging scenario as dangerous as the prickly cacti inhabiting the heat-filled landscapes of Tucson: a sweet teenage girl who might have a violent streak and a retired, street-wise agent who once lived among killers and has the resources to track devious prey. At first, Brigid is thrown off by Gemma-Kate’s avoidance, but then she becomes attracted to the bizarre notion that her niece might be trying to poison her as well.

To complicate matters, Brigid is approached by Tim and Jacquie Neilson whose son, Joe, died six months ago. The death was horrible, the initial police investigation concluding that it was an accidental drowning, perhaps even suicide. Considered a “goddamn homophobe” by Carlo and Mallory’s church friends, Tim’s denial of his stepson’s sexual orientation was thought to have contributed to Joe’s death. Even as Jacquie leaves a plea for help on Tim’s business card, Brigid is spurred on by the little questions that had never been raised by a responsible but rookie investigator who had never processed a death scene before, let alone the more challenging aspects of a scene that a drowning entails. Accidental asphyxiation with possible autoeroticism? Not so simple.

Brigid initially agrees with the police that there is no motive or opportunity for anything more dramatic or sinister. As she plunges further into the case, she begins to understand Jacque’s suspicions, along with her guilt. Soon enough Brigid is having trouble concentrating, her sudden nausea and trouble walking perhaps symptoms of a more serious disease. Gravitating between paranoid delusion and sanity, she fights to keep her stomach from turning over in a sickness that could either be caused, as Carlo suggests, by too much coffee or red wine--or perhaps by something far more sinister. Drawn into her own private hell, Brigid is soon convinced that Gemma-Kate is a beautiful, bewitching psychopath who is out to kill her.

While Tim and Jacquie are locked in a silent battle, an intimate warfare that only comes with marriage, looking for conspiracies around every corner, Brigid becomes embroiled in an investigation that is just a little too simple and has too few holes. Try as she might, she can find no link between the way she’s been feeling, her beloved poisoned pug, and the feelings of betrayal and rage towards her niece. She thinks about everything that has happened since Gemma-Kate arrived, and how she has single-handedly screwed up her contented life in Arizona. Masterman stays true to her plucky, no-nonsense heroine, getting to the heart of her protagonist as she tries to work through “the criminal element.”

Brigid finds herself fighting for her life, plunged into a new and terrifying darkness. The narrative rushes along, full of her messy but principled choices in what basically turns out to be good-versus-evil tale. From a charity function to a doctor’s office or even to a church, in the end, Masterman’s tale tells us that true evil can exist almost anywhere.