A group of radical activists set in modern-day London take over an energy company’s annual gala and take 300 hostages to expose the corruption of their bosses. Their righteous cause is hijacked by an extremist within their ranks who is willing to kill everyone in the building to send his anarchic message to the world. A former soldier turned window washer, played by Daisy Ridley, is suspended 50 stories above the building to save those trapped inside, including her younger brother.