The New York Times best-selling author of Magpie Murders and Moriarty brilliantly reinvents the classic crime novel once again with this clever and inventive mystery starring a fictional version of the author himself as the Watson to a modern-day Holmes, investigating a case involving buried secrets, murder, and a trail of bloody clues.

Billie, Mary Alice, Helen, and Natalie have worked for the Museum, an elite network of assassins, for 40 years. Now their talents are considered old-school and no one appreciates what they have to offer in an age that relies more on technology than people skills.

Egypt, 1936: When anthropology student Charlotte Cross is offered a coveted spot on an archaeological dig in Egypt’s Valley of the Kings, she leaps at the opportunity. That is until an unbearable tragedy strikes. New York City, 1978: Nineteen-year-old Annie Jenkins is thrilled when she lands an opportunity to work for former Vogue fashion editor Diana Vreeland, who’s in the midst of organizing the famous Met Gala, hosted at the museum and known across the city as the “party of the year.”

After more than a year of laying low, Billie, Helen, Mary Alice, and Natalie are called back into action. They have enjoyed their time off, but the lack of excitement is starting to chafe: a professional killer can only take so many watercolor classes and yoga sessions without itching to strangle someone...literally. When they receive a call from the head of the elite assassin organization known as the Museum, they are ready tackle the greatest challenge of their careers.

Chicky Diaz is everyone’s favorite doorman at the Bohemia, the most famous apartment house in the world, home of celebrities, financiers, and New York’s cultural elite. Up in the penthouse, Emily Longworth has the perfect-looking everything, all except her husband, whom she’d quietly loathed even before the recent revelations about where all the money comes from. But his wealth is immense, their prenup is iron-clad, and Emily can’t bring herself to leave him. Yet.