"21 Days" illustrates a love triangle starring Bete, her boyfriend, Jonas and Agatha, a childhood friend of Jonas. Told from three different points of view, the narrative was inspired by the songs "cardigan", "august" and "betty", from the album "folklore" by singer Taylor Swift.

Lia, a broken young woman, awaits an important call about a job response on her 22nd birthday, the first spent without her grandmother. While the cell phone doesn't stop ringing, Lia and her friends Tuco and Gael, get ready for an 80's themed party.