London, 1886. Unbeknown to his loyal wife Winnie, Soho shopkeeper Verloc works as a secret agent for the Russian government. Angry that Britain harbours violent anarchists, the Russians coerce Verloc into planting a bomb that will provoke the authorities into cracking down on these extremists. Caught between the Russians and the British police, Verloc reluctantly draws his own family into a tragic terror plot..