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 their hosts. Their just cause is hijacked by an extremist within their ranks who is ready to murder everyone in the building to send his anarchic message to the world. It belongs to a former military window washer, played by Daisey Ridley, who hangs himself 50 stories outside the building to save those trapped inside, including his younger brother.