On Vila Brasilândia, a favela in São Paulo, four Afro-Brazilian girls chase their dream of making a living from their music. Friends since childhood, Preta Negra Li, Bárbarah Leilah Moreno, Mayah Quelynah, and Lena Cindy Mendes quit singing backing vocals for a male rap group and form Antônia, their own band. Discovered by the smooth-talking manager Marcelo Diamante Thaíde, they begin to sing rap, MPB, pop and soul in bars and in middle-class parties.
Preta is the deep-voiced mother of a young daughter, Emília. Mayah is the most sexually provocative though single, and the high-voiced Lena lives alone with her boyfriend. Bárbarah Leilah Moreno is the sister of Duda, an athletic young man with whom she frequently practices martial arts. Duda's exposed homosexuality brings a rising action into the story in which his gay partner is killed by a gang and Duda himself injured. Duda, however, recovers; despite this sudden crisis, the future begins to look bright again as the band Antônia begins to take flight.
Just when the dream of the quartet seems to be turning true, their hopes are dashed by daily events, such as poverty, male oppression, and further street violence, which threaten the group and place the young women's friendship in jeopardy.
The conflict begins when Mayah flirts with Preta's estranged husband Ermano Fernando Macário, and Preta forces Mayah out of the group, deciding to raise Emília by herself with the help of her parents. Next, Lena reveals that she is pregnant and must quit the group after her boyfriend, who originally wanted an abortion, puts pressure on her to do so if they are to raise the child. Bárbarah, meanwhile, is walking home one night with Preta when she is confronted and harassed by a young member of the same gang who attacked her brother; she defends herself using martial arts, throwing him heavily to the ground and resulting in his hospitalization. The boy dies in the hospital and Bárbarah is arrested and imprisoned for manslaughter.
Preta, who struggles with her own personal troubles and the strain of raising her child alone, is the final member of Antônia left. At last unable to feel any desire to continue the group or rise to fame (as Marcelo encourages) if her friends cannot be with her, she goes to Mayah's house to apologize and reconcile. They, along with Lena, visit a grateful, teary-eyed Bárbarah in prison; they decide to spend their time with her writing a song about their experiences.
The scene changes to some point in the future in which all four members of Antônia are back together, singing onstage a liberation-themed song, Antônia.
