The power of Jugni is a curious thing.

 Jugni is a recurring character and metaphor and theme in Punjabi folk music.  A Jugni songs usually features a wide eyed innocent young woman arriving in a strange place, learning something new and providing illuminating commentary, sometimes humorous and sometimes sad.  Many Indian movies feature Jugni songs, in part because many Indian movies are about young women traveling to new places and having adventures.  The Jugni song in Happy Bhaag Jayegi (2016), for instance, plays while a runaway Indian bride is running through the streets in Pakistan.

The runaway bride in question is Harpreet "Happy" Kaur (Diana Penty).  Her father (Kanwaljit Singh) has arranged her marriage to local politician Baggu (Jimmy Shergill), but she's really in love with penniless struggling musician Guddu (Ali Fazal).  Guddu's friend has arranged for a flower truck to be parked outside the wedding venue, and at the appointed time, Happy sneaks away and jumps into . . . well, she jumps into the wrong truck, and the next morning she emerges from the basket she was hiding in, to find herself in a mansion in Lahore, Pakistan.

Bilal Ahmed (Abhay Deol), son of retired politician Javed Ahmed (Javed Sheikh) is very surprised to find an angry Indian woman in his living room.  Bilal has spent his entire life trying to live up to his father's expectations, including giving up cricket (because who ever heard of a cricketer becoming successful in Pakistani politics) and agreeing to a political betrothal to childhood friend Zoya (Momal Sheikh), and he knows that having an undocumented young Indian woman in a wedding dress in the house is probably a bad look, politically, but before he can really do anything about the situation, Happy runs away.

She is promptly arrested by comic relief policeman ASP Usman Afridi (Piyush Mishra), who has always wanted to arrest an Indian spy.  Happy tries to bluff her way out of the situation by claiming to be a guest of the Ahmed family, and that brings Bilal around to collect her.  He's taking her to be deported when they are stopped by Zoya.  After a very complicated and frantic series of explanations, Zoya points out the obvious: Happy can still cause trouble for the Ahmeds after being returned to India, so the best tactic is to keep her happy.  The best way to do that is to bring Guddu to India, get the young couple married, and then send them both home - once the marriage is finalized, Happy's father will have to accept it, and Baggu can learn to deal with disappointment.

The plan is unnecessarily complicated.  Bilal and Usman travel to India to find Guddu, posing as music producers.  Guddu is being held by Baggu, so Bilal and Usman have to strike a complicated balance in order to convince Guddu that Happy is in Lahore, without letting Baggu know.  They succeed, meaning everything will be fine as long as Baggu doesn't discover the truth.

Baggu discovers the truth, and the plot gets much more complicated, with everybody in Lahore, multiple kidnappings, Bilal reconsidering all of his life choices, and Zoya noticing just how close Bilal and Happy have become.  The only solution to everyone's problems is a mass wedding, I guess.

It sounds like a farce, and there are certainly jokes and moments of humor, but the characters take the situation completely seriously.  Abhay Deol has built his reputation on quirky art films, and even in a  commercial entertainer like this one he brings a quirky art film energy, while Momal Sheikh is a soap opera actress, and she brings that level of intensity to every scene.

In the end, our Jugni doesn't learn much from her journey.  Happy and Guddu are both fairly static characters, and while their situation has changed by the end of the film, their personalities really haven't.  Zoya and Bilal, on the other hand, change a lot; they start the movie as a man who gave up on his dreams and his bossy fiance, and they end with a recontextualized relationship and a new approach to life.  That's the real power of Jugni.