The young woman pulled an envelope from her purse, her hand shaking, and handed it to Agnes. “I found this under my doormat this morning.”

The envelope was scuffed with dirt. Agnes withdrew a pristine sheet of paper, careful to touch only one edge. Two sentences were written in a distinctive man’s script.

Be careful. We are being watched.

Swiss-American police officer Agnes Lüthi is on leave from her job in Lausanne, Switzerland, recovering from a nasty stab wound she sustained in her last case, when a former colleague invites her to the world’s premier watch and jewelry trade show at the grand Messe Basel Exhibition Hall. Little does Agnes know that another friend of hers, Julien Vallotton, is at the same show—and he’s looking for her.

Vallotton was friends with Guy Chavanon, a master watchmaker, who died a week ago, in an accident. At least that’s what the authorities are calling it. But shortly before his death, Chavanon had boasted that he’d discovered a new technique that would revolutionize the watchmaking industry, and his daughter believes he may have been killed for it.

Reluctantly, Agnes agrees to investigate Chavanon’s death. But the world of Swiss watchmaking, one of the country’s oldest arts, is guarded and secretive, and time is ticking fast for Agnes to find the killer—before he strikes again.