An intriguing tale, the story begins with PK (aamir) who happens to be an alien that comes to earth to study the human beings and lifestyle. But after reaching, he loses his tracker device through which he has to communicate to his spaceship. Not knowing the language, the people, PK has a tough time but he eventually finds a good friend in the form of Bhairav Singh (sanjay dutt). Few incidents occur and PK finds himself in Delhi in his search for tracker device. He is helped by Jagat Janani (anushka) in his search. What happens after that forms the rest.