In the summer of 1914 most of Europe plunged into a war so catastrophic that it unhinged the continent's politics and beliefs in a way that took generations to recover from. The disaster terrified its survivors, shocked that a civilization that had blandly assumed itself to be a model for the rest of the world had collapsed into a chaotic savagery beyond any comparison. In 1939 Europeans would initiate a second conflict that managed to be even worse...

In this dazzling historical mystery, John Stone, financier and arms dealer, dies falling out of a window at his London home. The quest to uncover the truth behind his death plays out against the backdrop of high-stakes international finance, Europe's first great age of espionage, and the start of the twentieth century's arms race.