While in his 20s, Karl Marx struggles to establish himself as a writer of political and sociological importance. He meets Friedrich Engels, a young man whose wealthy father owns factories. Engels' belief that the workers there and elsewhere, including children, are mistreated and underpaid matures. The men begin to work together to create a new political movement to reform and unite the impoverished workers. Eventually, the two stage a coup during a meeting of the League of the Just and create the Communist League in its place. The film ends with Marx and Engels writing and publishing their objectives as ''The Communist Manifesto''.