In modern-day London, a group of radical activists storm an energy company’s annual gala and take 300 hostages in order to expose the organizers’ corruption. Their righteous cause is hijacked by an extremist in their ranks, who is willing to murder everyone in the building to send his anarchic message to the world. It falls to a former soldier turned window cleaner, played by Ridley, dangling from the 50th floor outside the building, to save those trapped inside, including his younger brother.