The death of a Chinese immigrant, Wong Chut King, in San Francisco in 1900 would have been unremarkable if a swollen black lymph node-a sign of bubonic plague-hadn't been noticed on his groin. Empowered by racist pseudoscience, officials quarantined Chinatown. If the disease was not contained, San Francisco would become the American epicentre of an outbreak that had claimed ten million lives worldwide. To local press, railway barons and officials, such a possibility was inconceivable-or inconvenient. As they proceeded to obscure the threat, it fell to health official Rupert Blue to save the city and America from a gruesome fate.

In the tradition of Erik Larson and Steven Johnson, best-selling author David K. Randall spins a spellbinding account of Blue's race to understand the disease and contain its spread.