London, 1878. With faith in Scotland Yard shattered after a damning corruption investigation, Charles Lenox's detective agency is rapidly expanding. The gentleman sleuth has all the work he can handle, two children, and an intriguing new murder case.
But when Prime Minister Benjamin Disraeli offers him the opportunity to undertake a diplomatic mission for the Queen, Lenox welcomes the chance to satisfy an unfulfilled yearning: to travel to America. Arriving in New York, he begins to receive introductions into both its old Knickerbocker society and its new robber baron splendor. Then, a shock: the death of the season's most beautiful debutante, who appears to have thrown herself from a cliff. Or was it a suicide? Lenox’s reputation has preceded him to the States, and he is summoned to a magnificent Newport mansion to investigate the mysterious death. What ensues is a fiendish game of cat and mouse.