Sarah Pearse, author of ‘The Sanatorium’, concludes her trilogy with the mysterious story ‘The Wilds’

Sarah Pearse, author of ‘The Sanatorium’, concludes her trilogy with the mysterious story ‘The Wilds’

To stand out from the crowd, a good crime novel needs a baffling mystery, an engaging detective, and an intriguing selection of suspects, all with motive, opportunity, and ability to commit the most horrific murder. But these books also need an original setting, and the more contained and contained the better.

English author Sarah Pearse is well aware of this, as her first two novels were set in enclosed spaces. Her bestselling debut, “The Sanatorium,” was a locked-room thriller set in a snowy hotel in the Swiss Alps. In her sequel, “The Retreat,” the crime scene was similarly remote — a luxury spa resort on an island off the southwest coast of England.

Pearse’s latest novel is set largely in a Portuguese national park, a natural space wide enough to wander and, it seems, get lost in. “The Wilds” is the author’s third and final outing for Detective Elin Warner. It can be read as a final installment tying up loose ends, but also as a standalone story, one that will entice newcomers to check out the rest of the series.

Pearse introduces Kier, an English illustrator who lives a nomadic life with her American partner Zeph, a once-famous—and now infamous—chef. Kier and her brother Penn endured a childhood marked by domestic violence. Since then, she has been searching for peace and stability, while trying to suppress the fear that “the darkness inside will find its way to the surface.”

When Kier discovers Zeph following her and photographing his ex, she considers leaving a partner who has become both abusive and obsessive, then disappears during a trip to a national park in Portugal.

A few years later, Elin is on a hiking holiday in Portugal, to connect with her brother Isaac and to leave recent problems behind. After hearing of Kier’s disappearance in the national park she is traveling through, she swaps recreation for research.

Kier, an avid cartographer, left behind a map of the site. Elin uses it to retrace the steps of the missing woman, past landmarks ranging from pits to funeral pyres to the so-called Suicide Falls. It’s not long before she veers off the beaten path and into hostile territory, only to discover that those she encounters know far more than they let on.

The confined setting of Pearse’s previous books made the events creepy and claustrophobic. The author tries to recreate that sense of unease in “The Wilds,” but the shadowy shapes, faces in windows, and things that bang in the night don’t have the same chill factor. What should be exciting is often just atmospheric.

Pearse delivers on other levels, however. Her book is elegantly crafted and neatly plotted. The twisting narrative is filled with cryptic clues and unexpected developments. It makes for a satisfying thriller and a fitting swan song for a compelling creation.

Malcolm Forbes, who writes for The Economist and the Wall Street Journal, lives in Edinburgh, Scotland.

The wilderness

By means of: Sarah Pearse.

Publisher: Pamela Dorman Books, 400 pages, $30.