Paris, 1844, on the eve of the industrial revolution: the 26-year-old Karl Marx (August Diehl) lives with his wife Jenny (Vicky Krieps) in exile in France. When Marx was introduced to the young Friedrich Engels (Stefan Konarske) there, the notoriously bankrupt family man had nothing but contempt for the groomed bourgeoisie and the son of a factory owner. But the dandy Engels has just written about the impoverishment of the English proletariat, he loves Mary Burns, a cotton spinner and rebel of the English labor movement. Engels knows what he's talking about. It is the last piece of the puzzle that Marx is still missing from an unreserved description of the crisis. Marx and Engels have the same sense of humor and a common goal, they are great at getting drunk together, and they respect and inspire each other as comrades-in-arms. Together with Jenny Marx they develop writings that are supposed to ignite the revolution.