Berlin 1925. The Golden Twenties have firmly taken hold of the capital. The inflation has been overcome, and Berlin serves as the backdrop for the most expensive silent film of all time: Fritz Lang's "Metropolis." However, threatening letters to the lead actress Brigitte Helm cast a shadow over the production. Shortly thereafter, a dead extra is discovered on the set in Neubabelsberg. Former commissioner Robert Grenfeld investigates in the film set's surroundings and immerses himself in the futuristic metropolis.