When activists take over an energy company’s annual gala held at One Canada Square, Canary Wharf in London, some more radical members of their group take hostages and threaten to blow up the building if police intervene.
A dishonorably discharged but highly trained ex-soldier, who works as the building's window cleaner, attempts to save the hostages when she learns one of them is her older brother.
Set in present-day London, a group of radical activists take over an energy company's annual gala, seizing 300 hostages in order to expose the corruption of the 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 falls to an ex-soldier turned window cleaner, played by Ridley, suspended 50 storeys up on the outside of the building, to save those trapped inside, including her younger brother.