Set in present-day London, a group of radical activists take over the annual gala of an energy company, taking 300 hostages to expose the host’s corruption. Their righteous cause is hijacked by a radical within their ranks, who is prepared to kill everyone in the building to send his anarchic message to the world. It all comes down to a former soldier, a window cleaner, played by Daisy Ridley, suspended 50 stories from the outside of a building to rescue those trapped inside, including her younger brother.