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