To inveterate mystery consumers like myself, the Plot Twist is endlessly interesting. Generally it has to do with the culprit not being whom you suspect; the writer lays a trail to one or more characters, and then...it turns out that somebody you barely noticed (the butler?) did it. I think it is an effective device partly because it is based on real-life psychology. While a bad guy you don’t know is frightening in an abstract way, there is nothing scarier than the revelation of an evil secret self within a person you love and trust.

Clare Mackintosh is an expert at this sort of misdirection, as she proved in her first book, the bestselling thriller I LET YOU GO. For the sake of those who haven’t yet read this tale of a grieving woman and a fatal hit-and-run, I won’t go the spoiler route. But the surprises it delivers are so ingenious that after finishing the book, I wanted to go back and reread it in a whole different light.

You may feel the same way about I SEE YOU, Mackintosh’s second mystery, which has a couple of major, head-snapping twists toward the end. It begins, though, on familiar territory for this female city dweller. Please don’t think that I’m paranoid when I say that urban women are intrinsically at risk. We are forced to be cautious about crowded subway cars, empty subway cars, deserted lobbies and dark alleys, lest we be groped, robbed, raped or worse.

"[A]s smart, shivery entertainment that will keep you up way past bedtime, with an ending that will knock your socks off, I SEE YOU is a humdinger. And if you’re a commuter, it might make you think about changing your daily route."

I SEE YOU builds on that nerve-wracking reality when it introduces us to Zoe Walker, a 40-year-old divorced mother with a long commute --- same route, even the same seats, day after day --- to her bookkeeper/office-manager job in central London. One day, to her shock, she sees her own face staring out at her from a photograph in a newspaper ad, on the same page as promotions for escort services and chat lines. There’s a phone number listed, and a website, FindTheOne.com. Neither appears to function. She tries to forget it. But when she sees another woman’s picture in the same type of ad --- a woman who was recently robbed on the London Underground --- she starts to wonder if there’s a link between the photo and the crime (is she next?), and she contacts the police. Enter P.C. Kelly Swift.

Kelly is a copper with career problems. Because her sister was sexually assaulted while in college, she is especially sensitive to crimes against women. Four years ago, she physically attacked a rape suspect and was taken off British Transport Police’s Sexual Offenses Unit. Now, a temporary attachment to the Dip Squad, which nabs pickpockets in the Underground, gets her involved in Zoe’s case. It turns out there are quite a few women whose photos appeared in the same context as Zoe’s. When the police discover that one of them has been raped and another murdered, they launch a full-scale hunt for the mastermind behind the ads.

With some dazzling detective work and the help of a former boss, Kelly finesses her way onto the Murder Investigation Team (Mackintosh was a policewoman for 12 years before she turned to writing, so the procedural aspect of I SEE YOU is persuasive and abundantly detailed). The scheme the police uncover uses social media and high-tech manipulation to prey on women with a regular daily commute; it’s entirely modern, and utterly chilling. 

Mackintosh ramps up the tension by having Zoe and Kelly take turns telling the story. There is a third narrator, too, who breaks in every few chapters in italicized passages. It’s the voice of the villain, and it reeks of greed, cruelty and voyeurism. “Routine is comforting to you,” this anonymous presence intones to the hapless commuters whose predictability makes them vulnerable. “It’s familiar, reassuring. Routine makes you feel safe. Routine will kill you.”

As the investigation unfolds, it becomes frighteningly clear that the culprit could be someone close to Zoe, but that leaves plenty of choice: her cheating ex-husband, her less-than-truthful live-in lover, her obnoxious boss, her financially overextended neighbors, her actress daughter’s creepy new boyfriend. It takes many chapters for Mackintosh to populate this large school of red herrings, and after a while I became impatient, even slightly bored, with the lengthy set-up. I wanted the action to begin.

And then it did, and I couldn’t stop reading. The book began to accelerate --- wham! --- and soon, heart in mouth, eyes wide, I was following the fortunes of Kelly, Zoe, and Zoe’s daughter, Katie (who is in grave jeopardy as the book hurtles toward its climax).  Finally --- wham again! --- there are those amazing twists. (No peeking ahead.)

This is not a complex, character-driven mystery like those of Tana French, Ruth Rendell, Val McDermid, Elizabeth George, Susan Hill or Denise Mina (to name a few of my personal faves). But as smart, shivery entertainment that will keep you up way past bedtime, with an ending that will knock your socks off, I SEE YOU is a humdinger.

And if you’re a commuter, it might make you think about changing your daily route.