From gladysmitchell.com "Comrie Melrose, in his business life an easy-tempered literary agent, has planned a holiday that will double as a compatibility test: he will traverse the highlands of Scotland with his fiancee, the striking beauty Hera, to ensure that the couple can weather the ups-and-downs of both countryside and relationship. While walking The Way, Comrie and Hera encounter a number of fellow travelers including the garrulous mate's mate Carbridge and the handsome Mr. Todd. Both men notice Hera's presence--too much so--and Comrie rebukes them for their impudence, Todd with words and Carbridge with a swift shove. Soon Comrie and Hera are back on the trail to Fort William, hoping to leave the party far behind.

But fate is not so easily shaken: seeking shelter from a sudden rainstorm, the pair ducks into an abandoned stone farmhouse. In a dark passageway, Comrie stumbles literally upon a man's body, a dagger protruding from the lifeless form. Convinced that it is Carbridge (and not wishing to draw suspicion), the couple agrees to give no alarm, but to leave the murder site as soon as possible. Their shock is rather justified then when, some days later, an incontestably alive Carbridge saunters into their hotel, the rest of the hiking party trailing after him. The identity of the farmhouse body soon comes to light, but Comrie worries that his discovery that night is a portent of graver things to come.

And that is just how matters manage to play out. Reluctantly accepting an invitation for a reunion with the motley band of hikers, Comrie finds himself in a building on the campus of a polytechnic school. Anxious for some air, a helpful hangman-turned-housemaster suggests Comrie try a shadowy corridor for a bit of a stroll. At the end of the passage, Comrie finds the body of Carbridge, a Scottish sgian dubh dagger stuck into him. It suddenly appears that the hiker's party houses a murderer after all."