San Francisco, 1850. A city of sudden fortunes, desperate lives and secrets that cannot safely be entrusted to the living. Aidan O'Reilly arrives in the restless young city as an undertaker. Yet his true business is something altogether different. For those wealthy enough to require discretion, he provides places where stolen gold, forged documents, illicit fortunes and inconvenient histories can remain hidden. Then he meets Kate Cooper, a young woman whose extraordinary gift for numbers makes her invaluable—and whose courage makes her something more. Together they build a life and a business as San Francisco is transformed around them by fire, cholera, corruption and violence. As cemeteries are emptied to make way for profitable land, vigilantes patrol the streets and the city's most vulnerable are forced to fight for survival, Aidan and Kate find themselves drawn deeper into a world where morality is rarely simple and every secret has a price.