Set in a near-future dystopian London in which the majority of the citizens live underground in tunnels supplied with air through tiny vents. They live under a strict dictatorial regime but no one seems to be aware of that; this is all they have ever known. When Luca begins to notice the graffiti that is popping up around the city and branching out from one particular place, an old train station, he gets drawn into a rebel group who plan an attack on a small government base.