The Couple Next Door

Anne and Marco Conti attend a dinner party at the house next door. Their babysitter cancelled, the hosts do not want a baby present, and they leave their six-month-old daughter alone, returning every half hour to check.

At half past midnight they come home and the cot is empty.

They left the baby alone and checked every half hour, and the last check was too late.

Devmark’s reading — not a quotation from the book

The first chapter is among the most efficient in the category: a situation established, a decision made that the reader immediately recognises as a mistake, and a consequence delivered within a few pages.

The book's commercial success rests substantially on how quickly it starts. Lapena also establishes the dinner party's social dynamics in a few lines, so the reader understands exactly why the parents made a decision they should not have.

The parents' decision invites condemnation and the novel is aware of it, using the reader's disapproval as a tool.

Anne's postnatal depression and Marco's financial difficulties are both established, and the book is interested in how quickly sympathy is withdrawn from people who have made one visible error.

Every significant character is given motive, means and something to conceal, including both parents, the neighbours and Anne's wealthy and controlling parents.

The construction is conventional and is handled competently, with each revelation eliminating one possibility and introducing another. The rotation is rapid enough that no possibility is allowed to settle, which keeps the reader from committing to a theory and then losing interest.

The investigating officer is observant, unsentimental and openly suspicious of the parents, and his chapters supply the procedural spine.

He is a functional character rather than a developed one, and his role is to articulate the reader's suspicions and then complicate them. Lapena also uses him to supply information the parents do not have, which keeps the investigation moving when the domestic scenes stall.

The novel is written in present tense throughout, which is a common choice in the category and produces a sense of continuous immediacy.

It also flattens the prose considerably, and Lapena's style is deliberately unobtrusive to the point of transparency. It also removes the implication of a narrator recounting events afterwards, which would carry a guarantee of survival the book does not want to give.

Very short chapters, frequent viewpoint changes and a reveal roughly every thirty pages.

It is constructed entirely for momentum and achieves it. The book can be read in a few hours and is designed to be. There is also almost no description of anything, which is a deliberate choice: the book is a sequence of events and declines to slow for any of them.

Anne's family wealth, Marco's failing business and the financial dependence between them are the plot's actual engine.

The novel is better on this than on anything else: the specific humiliation of needing your wife's father's money is well observed. Anne's father in particular is drawn well, and his contempt for his son-in-law is expressed entirely through offers of assistance.

Several developments require characters to behave in ways that strain plausibility, particularly in the final third.

The book prioritises reversal over coherence, which is a legitimate choice for the category and will frustrate readers who want the plot to hold up afterwards. Several characters also act on information they should not have, and the novel does not always account for how they obtained it.

The people are thin, defined largely by their secrets, and the novel does not attempt interiority beyond what the plot requires.

This is the clearest difference between Lapena and the stronger writers in this group, and it is a deliberate trade for pace. Anne's postnatal depression in particular is used as a plot mechanism more than as a condition, which is the book's least defensible decision.

It resolves the disappearance and adds a final turn in the last pages that recontextualises one relationship.

The closing device is effective and is also the point at which the novel's preference for surprise over consistency is most visible. It also leaves one thread deliberately unresolved, which Lapena has used in several subsequent books and which readers find either effective or evasive.

Readers who want maximum plot velocity and are untroubled by thin characterisation.

It is the most purely commercial book in this section and entirely honest about that. Readers who want the domestic thriller done with more substance should read Flynn or French instead. It was also a very substantial commercial success, and its shape has been widely copied, which makes it worth reading as a specimen of the category.