The film starts off with a Pakistani village household cheering for Pakistan while watching its nail biting crucial cricket match with India on television. Inspired by the ace Pakistani cricketer Shahid Afridi, a to be mother from the household names her daughter as Shahida (Harshaali Malhotra). The girl despite being beautiful and expressive does not speak a word, which worries her parents day after day.
On the advice of an elderly person in the family, Shahida’s mother decides to take Shahida to a wish-fulfilling holy dargah in Delhi, India. On their way back to Pakistan, their train halts due to a technical failure. That’s when the innocent and animal loving Shahida sees a helpless lamb fallen in a pit. She gets down from the train and just when she rescues the lamb, the train starts moving, thus leaving her behind in an unknown country all alone. She quickly boards the next immediate train and reaches Delhi. It is here when she meets the extremely God fearing and a devout Hanuman bhakth Pavan Kumar Chaturvedi aka Bajrangi (Salman Khan).
With the intention of helping the little girl who cannot talk, Bajrangi takes her home, only to be ridiculed by his family members. The only person who stands by him is his to-be-wife Rasika (Kareena Kapoor). Pavan and Rasika try their level best to ‘decode’ the identity of the child by dropping names of almost all the Indian states, but in vain. Havoc strikes their family household when they discover that Munni (aka Shahida) not only eats meat, but is also a Muslim and above all… a Pakistani! That’s when Pavan decides to brave all the odds (visa issues, passport problems etc).
Despite all the odds, when Bajrangi manages to cross the Indo-Pak border, but gets caught by the Pakistan police, who label him off as an Indian spy. That’s when Bajrangi encounters a freelance news reporter Chaand Nawab (Nawazuddin Siddiqui), who shoots the whole Pavan-Munni ‘adventures’ on his handycam, hoping this will be his big ticket to name and fame as a journalist. However, as he discovers their Pavan’s good intentions, he too joins the duo in their journey and helps them out.
Does Chaand Nawab manage to ‘encash’ on the Pavan-Munni story in order to be taken seriously as a journalist, does Pavan succeed in uniting Munni with her parents, does the ever-truthful Pavan manage to prove his innocence of him not being a spy before the Pakistani police and how does the simpleton Bajrangi gets transformed into ‘Bajrangi Bhaijaan’ is what forms the rest of the story.
*** HQ ***