Harry (Akshay Kumar) is a barber who frequently gets bizarre flashes of a past era. He runs a barber shop in London with his brothers Roy (Riteish Deshmukh) and Max (Bobby Deol). The three brothers had misplaced a bag of 5 million pounds which belonged to gangster Michael Bhai. His henchman Big Bhai (Manoj Pahwa) constantly demands the money. To fulfil this demand, the three brothers get engaged to the three daughters of London's rich business tycoon Thakral (Ranjeet): Harry is dating Pooja (Pooja Hegde), Roy is dating Neha (Kriti Kharbanda) and Max is dating Kriti (Kriti Sanon). Mysterious circumstances cause the destination wedding to take place in Sitamgarh, India. On arriving in Sitamgarh, Aakhri Pasta (Chunky Pandey), a bellboy at their hotel, recognises them as reincarnations of people that lived 600 years ago, i.e. in 1419. Harry realises that the flashes he sees have something to do with what Pasta was talking about. To meet him, Harry drives to the nearby town of Madhavgarh where he starts to see the flashes clearly.
In 1419, Rajkumar Bala Dev Singh (Akshay Kumar) of Madhavgarh was banished by his father, Maharaj Parikshitap (Parikshit Sahni), since Bala tried to kill him to become King. Bala's servant Pehla Pasta (Chunky Pandey) informs him of Sitamgarh - a nearby kingdom whose King, Maharaj Surya Singh Rana (Ranjeet), is looking for grooms for his three daughters: Rajkumari Madhu (Kriti Sanon), Rajkumari Mala (Pooja Hegde) and Rajkumari Meena (Kriti Kharbanda). Bala plans to marry Rajkumari Madhu, the eldest Princess, so that he becomes the Maharaj of Sitamgarh.
Bala meets Bangdu Maharaj (Riteish Deshmukh), an effeminate dance teacher who has an affair with Mala. Meena is secretly in love with the brave bodyguard of the three princesses, Dharamputra (Bobby Deol). Bala helps the two couples get together and enlists their help for uniting him with Madhu. The plan works and Maharaj Surya Singh Rana announces the wedding of Madhu with Bala, Mala with Bangdu, and Meena with Dharamputra. However, Suryabhan (Sharad Kelkar), Surya Singh Rana's nephew, wants the throne for himself. He kills the brother of Sitamgarh's enemy clan's leader, Gama (Rana Daggubati) and frames the three couples for it. On the day of the wedding, Gama storms into the palace and fights them to avenge his brother. During the fight, Bala realises that he now truly loves Madhu, even though initially she was just the path to the throne for him. During the fight, the wedding mandap (altar) collapses and kills the three couples along with Gama.
Back in the present, Harry realises that the grooms are set to marry the wrong brides. Pasta helps Harry remind Roy and Max of their lives as Bangdu Maharaj and Dharamputra, respectively. Just then, they are introduced to Pappu Rangeela (Rana Daggubati), a qawwali singer and the brother of the girls. He is the reincarnation of Gama but has no recollection of his past life. Meanwhile, Pasta finds a painting of their past lives' wedding day which shows Bala with Madhu, Bangdu with Mala, and Dharamputra with Meena. Before they can show this painting to the girls to remind them of their past lives, it gets in the hands of Pappu Rangeela and he remembers his life as Gama.
Pappu crashes the wedding and a fight plays out. The fight makes Pooja and Neha remember everything. Soon, Michael Bhai (Sharad Kelkar), now revealed to be the reincarnation of Suryabhan, shows up at the wedding for his money and shoots Gama. Kriti remembers everything when she sees Michael Bhai and also reveals that the wedding mandap hadn't collapsed on its own - it was broken down by Suryabhan to kill everyone so that he could be the Maharaj of Sitamgarh. Michael Bhai recounts his past life and boasts how he got Gama's brother killed. Pappu Rangeela hears this and pushes Michael Bhai into the collapsing mandap, thus getting his revenge.
The film ends on a happy note with Harry marrying Kriti, Roy marrying Pooja and Max marrying Neha, thus completing their 600-year-old love story.