What if you could peer into the minds of an entire population? What if you could target the weakest with rumours that only they saw? In 2016, an obscure British military contractor turned the world upside down. Funded by a billionaire on a crusade to start his own far-right insurgency, Cambridge Analytica combined psychological research with private Facebook data to make an invisible weapon with the power to change what voters perceived as real. The firm was created to launch the then unknown Steve Bannon's ideological assault on America.