Loki brings the trajectory of Arnaldo Baptista from childhood, passing through the most successful phase as leader of the Mutantes, marriage to singer Rita Lee and then separation. He also goes through the depression that devastated his life after the group ended and that led him to attempt suicide, his solo career, rapprochement with his brother and member of the Mutantes, Sérgio Dias, culminating in the band's return in 2006..