In a 120-storey underground bunker, the rulers lied, saying the surface had been destroyed by radiation and poison gas and that humans could only survive in the bunker; in reality, the surface was still sunny and bright. The elite at the top enjoyed resources and privileges, the middle layers managed order, and the workers at the bottom were trapped in the industrial zone. Calum, a maintenance worker, only wanted to keep his adopted son Toby safe and growing up well, but after Toby discovered a mysterious arrow, Calum realised the blueprints were fake. To find the truth, Calum decided to take the dangerous path of resisting the bunker's lies and class oppression.
