Set in 1960s Bombay, the film tells the story of Balraj (Ranbir Kapoor), a street fighter/boxer who is in love with the jazz singer Rosie. Seeing Rosie (Anushka Sharma) with wealthy men further sparks his dream of becoming a "big-shot", believing that if he manages to become rich, he might win Rosie's heart. Balraj and his friend Chimman (Satyadeep Misra) then catch the eye of Kaizad Khambatta (Karan Johar), a wealthy businessman who is impressed by Balraj and offers him to manage his club "Bombay Velvet", which Khambatta uses to further his illegal tasks and activities. He also nicknames Balraj "Johnny", which then becomes his identification. As well as this, Johnny and Chimman fulfill minor tasks for Khambatta, including capturing a dirty photograph of a minister who Khambatta wants to blackmail. This news reaches Jimmy Mistri, a media reporter, who also happens to be the same wealthy man Johnny had previously seen with Rosie.
In 1961, in a little village in the middle of the Guinean tropical forest, a music band is born. This band will soon become one of the biggest orchestras of modern Africa. It is Bembeya Jazz. This orchestra, symbolizing the Guinean revolution of Ségou Touré, managed to rock the whole African continent with their music. Forty years later, we go back to its roots. Besides the difficulties, the “Bembeya mystery” is still alive: the legend continues!