The psychological thriller follows the story of Verloc, owner of a seedy shop in the heart of Soho. Unbeknownst to his loyal wife Winnie, Verloc also works for the Russian embassy, spying on a group of anarchists. The Russians are furious with the English establishment's indifference to the anarchist threat gripping the rest of Europe. So Verloc is assigned a mission: blow up the Greenwich Observatory and make it look like a terrorist attack to provoke a crackdown. Should he fail, Verloc's real identity as a spy will be exposed to his vicious comrades.