Hundreds of peaceful civilians were slaughtered in the Amritsar Massacre of 13 April 1919, after British troops opened fire without warning. According to legend, Udham Singh was among the injured that day, and he vowed to take revenge. More than twenty years later, in a Westminster hall, he fulfilled that promise when he gunned down in cold blood the man ultimately responsible, Sir Michael O'Dwyer.

But what happened in the intervening years? In this sweeping narrative that takes the reader across four continents, Anita Anand separates reality from myth to reveal Singh's astonishing story. She brilliantly pieces together his movements, discovering surprising new links that take us from Jazz Age New York to the shady world of international spy rings. The Patient Assassin shines a devastating light on one of the Raj's most horrific events, but reads like a taut thriller.