Nugent narrates her dark literary mystery in alternating chapters that feature reclusive Lydia Fitzimonds, her son Laurence, and Karen, the tortured working-class sister of missing Annie Doyle. Each section of the book holds a clever revelation of Lydia and her husband, Andrew. A fascinating mix of snobbery and despair, Lydia's sociopathic tendencies impact Laurence, Karen and everyone else drawn to her charming veneer. Lydia is endowed with great beauty and class, but she suffered from a harrowing childhood and has never taken responsibility for the events surrounding the suspicious death of her twin sister.
Andrew, a prestigious Dublin high court judge, regards himself as an icon of moral purity. His only slip-up is the dead girl lying in the trunk of his car. Lydia has warned Andrew to say as little as possible. Stressed and shocked, Lydia has taken to locking herself in her bedroom while she waits for the axe to fall. With the TV news blaring about the 22-year-old Dublin woman who went missing eleven days ago, Lydia wonders whether Annie's death was just "an awful nightmare."
Karen and her parents make a plea to the media that Annie was not kind of girl to put herself in the way of trouble. The last time Karen saw Annie was in her studio flat on Hanbury street. Detective Sergeant O'Toole Detective Mooney leads the investigation, but they can shed little light on her disappearance. The later reports suggest that Annie was leading a sordid life and had a reputation. More salacious reports hint at an unfortunate history of institutionalization and shoplifting, implying that Annie was a prostitute. While O'Toole says that she'll eventually turn up, Karen insists that her sister had never disappeared for so long before.
Karen goes on the hunt, ignoring the whims of Dessie, her over-possessive husband. She knows something is horribly wrong, but over the ensuing weeks and months she constructs a careful façade to hide the damage Annie's vanishing has wrought on her and her parents. Laurence has his own suspicions. An insecure, obese boy who finds deception difficult, he hates that his parents are acting as though Annie Doyle vanished into thin air. At first, the idea of his father being involved in her disappearance is absolutely preposterous. When Laurence learns that an old blue Jaguar was seen visiting Annie's flat over recent months, fear and anxiety sweep back into his heart. He begins having nightmares in which he's having sex with Annie in his girlfriend's distorted bedroom. In other dreams, he's stabbing her viciously with her father's silver letter opener.
For a boy who grew up with an overprotective mother and a father who indulges him like a boy, Laurence is trying for a certain independence, fawning over girls and a home. He tries but cannot hide Lydia's secrets--and the secret that lies in the backyard of Avalon, Lydia's ancestral home. Lydia and Andrew carry on as if nothing has happened, while Laurence lives a waking nightmare in dread of every knock on the door. According to Machiavellian Lydia, Annie Doyle was nothing more than an addict and prostitute with a harelip who was utterly shameless, dishonest and cruel.
Nugent constructs a marvelous web of atmosphere and illusion as she moves between the voices of Lydia, Laurence and Karen. As Annie's vanishing causes upset and grief that ripples outward, fearful Laurence learns that cannot trust Helen or his mother and father. He becomes obese again, "revolting and disgusting." Karen pursues a lucrative modeling career, but she can't forget about Annie and that there's a possible murderer out there who could have done it before, destroying someone else's family. Karen eventually enters the orbit of Laurence and then Lydia, who ends up emotionally blackmailing her. Lydia is the novel's dark heart, turning on the flip of a coin from an emotional wreck to a sort of robot, clinical, callous and detached.
Karen, Laurence and Lydia seem adrift on a menacing current until the last shock arrives. What was once a perfect plan jolts Annie's whereabouts back into the forefront in a shocking conclusion. Laurence is forced to pay the price after, decades later, he exhumes his parents' secrets. The ultimate revelation strikes with quiet but lethal force. Lying in Wait is mosaic of such fragments, so cunningly assembled that the finished pattern seems as inevitable as it is harmonious. What must happen does happen in this elegiac thriller; we just can't see it coming.