To stand out from the pack, a good crime novel needs a baffling mystery, an engaging detective and an intriguing selection of suspects, all in possession of a motive, an opportunity and an ability to commit murder most foul. But these books also need an original location, and the more closed-off and hemmed-in the better.

English author Sarah Pearse is well aware of this as her first two novels played out in confined spaces. Her bestselling debut, "The Sanatorium," was a locked-room thriller set in a snowbound hotel in the Swiss Alps. In her follow-up, "The Retreat," the scene of the crime was equally remote — a luxury wellness resort on an island off England's southwest coast.

Pearse's latest novel largely unfolds in a Portuguese national park, a natural space wide enough to wander and, seemingly, get lost in. "The Wilds" is the author's third and final outing for Detective Elin Warner. It can be read as a last installment that ties 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 childhoods marred by family violence. Since then, she has been on the move in search of calm and stability while trying to suppress the fear that "the darkness inside will find its way to the surface."

When Kier discovers Zeph has been tracking her and photographing his ex, she weighs up leaving a partner who has become both abusive and obsessive. Then, on a trip to a national park in Portugal, she vanishes.

Several years later, Elin is on a hiking vacation in Portugal, attempting to reconnect with brother Isaac and put recent troubles behind her. After learning of Kier's disappearance in the national park she is trekking through, she swaps recreation for investigation.

Kier, a keen cartographer, left behind a map of the place. Elin uses it to retrace the missing woman's steps, navigating landmarks that range from pits to pyres to the so-called Suicide Falls. It isn't long before she veers off the beaten track into hostile territory and finds that those she encounters know a lot more than they are letting on.

The circumscribed settings of Pearse's previous books rendered the proceedings creepy and claustrophobic. The author tries to replicate that sense of disquiet in "The Wilds" but the shadowy shapes, faces at windows and things going bump in the night don't have the same chill factor. What should be suspenseful is often just atmospheric.

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

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

The Wilds

By: Sarah Pearse.

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