Aldo Morosini, the antique dealer-detective, embarks upon a new investigation, this one involving a queen and her jewelry.

Aldo Morosini and his fellow collectors have lent pieces of jewelry that once belonged to the sovereign for “The Magic of the Queen”, an exhibition whose theme is Marie Antoinette at the Trianon. Crowds flock to the opening, and in the crush of people, a murder is committed. “The Queen's Avenger” claims responsibility for the crime, and others will follow. And as they do, Morosini finds himself increasingly suspect in the eyes of Commissioner Lemercier. Among the pieces at the exhibition is an earring, a diamond “tear” (judged false by Morosini) lent by a certain Caroline Autié. The original pair were allegedly among Marie Antoinette's private jewels that disappeared during the flight to Varennes. But the young Caroline is unaware of the existence of the earring and, in fact, says she lent nothing to the exhibition. The only piece of jewelry Marie Antoinette once offered her family was a pendant, she declares, and she has no idea what has become of it. But she lives on the outskirts of Versailles, in a disquietingly mysterious house where strange things happen. Aldo Morosini finds himself confronted by an accumulation of problems, including a contentious police commissioner, a seemingly ubiquitous assassin, and the mysteries of Versailles--of the palace, the gardens, even the city itself, where every face he encounters seems to be a mask.