The movie, in its first scene, shows how great life is for the elite and how bad it is for the lower class. Freders, the son of the boss of metropolis falls for Maria, who is a leader for the unjust conditions for the workers; this information is kept a secret from her boss. When Rotwang and Freders dad discover Maria's secret, they kidnap her and transform Hel to be an exact copy of her to ruin her reputation. Hel behaves irresponsibly and immorally so the workers will discredit her and their spirit will be broken.
Then, in the nick of time, Freders rescues Maria and together they stop the revolution and bring back the feeling of peace and security between the bosses and the workers. Hel is destroyed, Rotwang dies and Freders and Maria live happily ever after.
"Metropolis is a story about the people whose backs wealth and success is built upon. It clearly illustrates the dichotomy between those that do, and those that benefit by the sweat of others. The thinkers of Metropolis enjoy a luxurious lifestyle, but their success comes at the price of treating the workers like slaves and deprives them of their individuality." (http://www.ram.org/ramblings/movies/metropolis.html)
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