February 1891: New York's Metropolitan Museum of Art is hosting an exhibition of Chinese art objects, timed to coincide with the arrival of a new Chinese cultural attaché, Lord Peng. Prudence and Geoffrey are invited to attend the opening ceremonies. But among the throng of dignitaries making their way through the galleries is one decidedly unwelcome and unexpected visitor--an assassin who stabs the attaché to death, then flees through Central Park.

As witnesses, Prudence and Geoffrey quickly become immersed in the case and join former New York detective Warren Lowry in investigating the murder. But there are complications. The Peng family will no longer enjoy diplomatic standing and is threatened by deportation and possible disgrace or execution in their homeland. Desperate to remain in the West, they flee into the labyrinth of Chinatown, enlisting the protection of a long-lost uncle, now the leader of one of the city's most feared Tongs. But that alliance comes with a price; Peng's son must become his uncle's apprentice in crime, while his eldest daughter will be forced to marry a Tong leader she has never met.

With a killer still at large, bent on revenge for a long-ago injustice and determined to eliminate every member of the Peng family, Prudence and Geoffrey are plunged into the heart of a culture about which they know very little. Each foray into the narrow streets and alleyways of Chinatown could be their last.