An Unwanted Guest

An Unwanted Guest by Shari Lapena is a standalone thriller published in 2018, her third novel and a New York Times and Sunday Times bestseller. It marks a deliberate departure from the domestic marital suspense of The Couple Next Door and A Stranger in the House, reaching instead for the atmosphere and mechanics of the classic golden-age whodunit - a locked room, a snowstorm, and a cast of characters none of whom are quite who they seem.

Mitchell's Inn sits deep in the Catskills, the kind of beautifully remote mountain lodge that promises a genuine escape from the world. The guests who arrive on a grey Friday in winter have come for exactly that - a long weekend of good wine, no signal, and enforced relaxation. Gwen and Riley are old friends, the trip a gesture of support after Riley's return from a difficult assignment. Lauren and Ian are navigating the early stages of a new relationship. Dana and Mathew are newly engaged. A criminal defence attorney, a true crime writer, and a handful of others round out the party, each carrying enough personal history to keep any dinner conversation complicated. By Saturday morning, one of them is dead at the bottom of the grand staircase. The storm has knocked out both the power and the phone lines. Nobody is going anywhere. And nobody, the remaining guests are beginning to realise, is entirely trustworthy.

What makes this a distinctly different Lapena experience from her other novels is how openly she leans into the Agatha Christie inheritance - the isolated setting, the ensemble of suspects with interlocking secrets, the amateur deduction filling the space where police procedure usually sits. The Murder Mystery here is a genuine whodunit rather than a domestic thriller, and readers who try to solve it as they go will find plenty of planted details to misread, red herrings to pursue, and Dark Secrets in almost every character's luggage to weigh against the mounting body count.

The snowbound inn does real atmospheric work. Without power or outside contact, the social dynamics among the stranded guests deteriorate with convincing speed - suspicion, old grievances, and the particular tension of being trapped in comfortable proximity with someone who may have just killed a person you know giving the Isolation & Survival stakes a claustrophobic edge. Lapena tells the story across Multiple POV chapters, moving between the ensemble cast to build a picture of the inn's weekend in which each character's account is partial, shaped by what they're concealing as much as by what they actually saw.

The Mystery and Secrets Revealed across the novel's back half arrive at pace once the body count starts rising, and the Twist Ending operates on the same two-beat structure as The Couple Next Door - a resolution that turns out not to be quite the whole story. Reception has been warmly divided along familiar Lapena lines: readers who come for atmosphere and pace tend to find this among her most purely enjoyable, while those who want deeper character interiority or tighter prose find it lighter than her domestic work. By wide consensus, though, it's the most purely fun entry in her catalogue - the book to recommend to readers who love Christie and want something that captures that spirit with a sharper, more contemporary edge.