Listening when far-right extremists think no one is listening—this is the goal of British anti-fascist group Hope Not Hate. With a camera hidden in his shirt button, journalist Harry Shukman spends months infiltrating far-right circles at great personal risk. The activists uncover multimillion-dollar sums flowing straight from Silicon Valley and pay a heavy price: Their private addresses and photos are circulated through far-right networks. How long will they be able to remain undercover?