Set in modern-day London, a group of radical activists take over an energy company’s annual gala and take 300 hostages to expose their hosts’ corruption. Their just cause is hijacked by an extremist within their ranks who is ready to kill everyone in the building to send his anarchic message to the world. A former soldier, played by Daisey Ridley, is tasked with hanging 50 stories from the outside of the building and rescuing those trapped inside, including her younger brother.