Eternamente Pagu is a biographical film about Patrícia Galvão, best known as Pagu, a Brazilian political, literary and artistic activist. An important figure of the Brazilian Modernism, Pagu was also a militant for the Brazilian Communist Party after she married writer Oswald de Andrade. She broke up with Andrade and, as a journalist was arrested by the Dictatorship of Getúlio Vargas. After she left prison, she abandoned Communism in favor of Trotskyist Socialism, married Geraldo Ferraz, and started a career as theatre director.

An actor who was famous and successful when he was just a 15-year-old teenager starring in the movie "The Pool Cleaner." Today, he finds himself without a job, without money and without friends, still living in his parents' house.

Paula and Rogelio's whirlwind romance leads the two to get married in secret. When Paula arrives at Rogelio's family home, his controlling and manipulative mother Martina becomes obsessed with ruining Paula's life.