Lt. Disher hops in a taxi while on a date and finds that his cab driver has been stabbed to death with an antique hatpin. The next day, Monk is called in to investigate. Stottlemeyer gives a rundown of evidence found in the cab. There's the hatpin, which implies that the killer was a woman. Also found was a torn scrap of paper with a design on it. Finally, there's a charm bracelet which was likely worn by the killer, from which Monk and the gang create a profile of their suspect.
Police research sends Monk to an outreach center for refugees from the Eastern European nation of Zemenia. One of the center's employees, a woman named Leyla Zlatavich, fits the charm bracelet profile perfectly. If that weren't enough, the scrap of paper found at the scene is a match for Zemenian currency. Despite the preponderance of evidence, Monk insists that Leyla is innocent. Natalie suspects that Monk is attracted to Leyla, but Monk angrily denies it.
The police bring Leyla in for questioning, after which she pays a visit to Monk. Monk is nervous in Leyla's presence; he obviously has a crush on this most beautiful of suspects. Leyla maintains her innocence and wants to hire Monk to clear her of the taxi driver's death. Monk agrees to work for free, and the two meet for dinner later that night.
As Monk gets to know Leyla better, his fondness for her only grows stronger. She's kind, intelligent, and courageous, and she seems to understand Monk. While they eat, Monk learns about the Butcher of Zemenia, an international fugitive who killed much of Leyla's family back in her native land. Monk sees a picture of the Butcher and recognizes him as the murdered cab driver. This isn't good news for Leyla because now she has a motive.