RK is a filmmaker making a new picture in which he also plays the lead character of Mahboob. With a high-maintenance actress as the female lead Gulabo, the film-within-a film is a retro tribute to the cinema of the 1960s. When shooting is finished, and the editing begins, RK has a sinking feeling that the film is not going to come together.
Sure enough, one afternoon RK gets a call from the editing room - something terrible has happened. Mahboob has "run away, run out of the film" and somehow has entered the real world. Mahboob is fleeing from the film's cartoonish killers when RK finds him and brings him home to his wife and kids.
Mahboob has no idea where he is from, or that he is any different from people around him.