Sometimes the more hideous the secrets, the more carefully the mask is constructed. Just ask vulnerable Rachel, a self-confessed alcoholic. Rachel loves the taste of her tangy, cold pre-mixed gin and tonic from the cans in the plastic bag at her feet. As the 8:04 slow train from Ashbury to Euston jolts, scrapes, and screeches into motion--in a daily commute that can test the patience of the most seasoned traveler--Rachel knows she doesn’t have to feel guilty about drinking.

It’s a Monday morning in July 2013, the sun shining in a cloudless sky and bathing Rachel in a beautiful, drunken haze. Although Rachel’s life has recently turned into a toxic waste dump, she can’t wait to get back into London and spend her day roaming the streets. She’s fooling herself and her kindly flatmate, Cathy, into thinking she still has a job. Rachel would much rather be looking out at the houses beside track number 15, and the quaint Victorian semi overlooking its narrow well-tended garden. Here she spies the attractive occupants, Jason and Jess: he dark-haired, well-built, the strong protective kind; she a beauty, pale-skinned and blonde.

Rachel’s not the girl she used to be. She’s no longer desirable and has put on weight; her is face puffy from drinking. As she walks down to the off-license to buy yet another bottle of wine, people can see “the damage written all over her.” But as she fantasizes about Jason and Jess and their perfect lives, she sees another Victorian semi on the tracks--the one she once owned with her ex-husband, Tom. As the months of estrangement pass, Rachel and Tom are frequently at odds with one another: Rachel is devastated that Tom fell out of love with her and moved into their house with his current wife, Anna.

Tom is frequently exhausted by the demands of his drunk, emotionally unstable ex-wife, who now lives as a lodger in a small second bedroom of Cathy’s bland and inoffensive duplex. Rachel looks at Tom and Anna’s carefully calibrated life and is flooded by hatred. Obsessed each morning with Jess and Jason (who later become Scott and Megan), Rachel--evermore defeated by drink--refuses to see consequences of her actions. Filled with an animosity that she can’t seem to control, she fanatically asks for forgiveness from Tom for all the things she says and does.

Thus begins Hawkins’ Machiavellian slow-burn thriller, unfolding with just enough information to make us think we’ve figured things out before she hits the reader with another plot twist that manipulates our gauzy impressions of Rachel, Tom, Anna, Megan and Scott. The reader is caught between admiration and real dislike for each flawed and selfish character, only to be shocked by revelations that give new meaning to marital dysfunction.

Megan, meanwhile, has gone missing. Bored mad and a little curious, she worked as a child-minder for Tom and Anna--rather ironic considering that later Rachel suddenly befriends Scott, and her impressions about the perfect couple are finally shattered. As the narrative unfolds in Rachel, Megan, and Anna’s distracted voices, Rachel tears herself apart about the terrible act she was supposed to have committed that Saturday night on Blenheim Road. Somehow in a wasted, drunken stupor, she blacked it out: “I knew it when I looked into that dark tunnel under the railway line, my blood turning to ice water in my veins.”

Neither bombastic, vitriolic Scott nor Megan’s therapist, Kamal, do themselves any favors in those first perilous days of the police investigation. Unable to help and unable to offer any real clues to the police, Detective Inspector Gaskill is convinced that Scott and an increasingly erratic Rachel are covering up half-lies and generally making the efforts to find Megan harder.

Rachel feels like she’s no longer part of the mystery connected to the girl on the train, “going back and forth without point or purpose.” She has become something far more subversive. She tries to get things straight in her head, to piece it all together from the memories, flashbacks, and half-broken dreams that happened on that Saturday night. Her existence is like “a grey blur” with Megan continuing to smile at the camera, “still beautiful, untouched.”

Regardless of its predictable plot, the novel is far more than your typical murder thriller. It is about one woman’s voracious need to be loved and her need to come to terms with disappointment on a grand scale when she finally realizes that the greatest happiness that she has ever known is an illusion.