In 2020, an aged Manu Randhawa runs away from a hospital in London. She meets an immigration lawyer, Puru Patel, and asks him to connect her with Hardayal "Hardy" Singh Dhillon, her ex-lover. In Laltu, Punjab, an aged Hardy is ecstatic to receive Manu's call after 25 years. She asks him to meet her in Dubai, so that he can bring her back to India through the "Dunki" route.
In 1995, Manu and her friends, Buggu and Balli, live in Laltu, and yearn to immigrate to London for a better life. Poor and uneducated, they are unable to procure a visa, despite trying various methods. One day, Hardy, an ex-Army officer, arrives in their village. Manu's brother had saved his life in combat, and he has come back to return his personal belongings, but realises that he has died in an accident, leaving Manu and her family in a poor financial situation. He promises to help Manu reach London, as a return for her brother's kindness. They enroll at an IELTS coaching class taught by Geetu Gulati, where they meet Sukhi. Sukhi wants to immigrate to London to save his ex-girlfriend, who was married off to an NRI man who physically abuses her. Balli eventually clears the exams, and the rest fail.
Once in London, Balli tells Sukhi that his ex has died by suicide after learning about Sukhi failing in IELTS, due to which Sukhi immolates himself. Traumatised, Hardy promises to take Manu and Buggu to London himself through the "Dunki" route. After a treacherous journey through Pakistan, Afghanistan, Iran and Turkey, during which three of their co-passengers are killed and Manu is saved from sexual assault by Hardy, they reach London. There they meet Puru Patel, who advises Manu to enter into a sham marriage to get her visa. She agrees, and marries a drug addict. While in church, Hardy is angered by his attempt to kiss Manu, and they engage in a fight due to which they are both arrested. In court, Puru advises them to seek right of asylum to stay in the country by claiming that their lives are under threat in India. As an ex-Indian Army officer, Hardy refuses to betray his country, but the rest agree on doing so. Hardy is soon deported to India, while the rest become British citizens, initially working as living statues.
In the present day, Manu tells Hardy that she wants to go back home, as she is dying of cancer. They try to leave for India via cargo containers. They eventually fool immigration officials into believing that they were Indian citizens traveling illegally to London, and are thus sent back to India. Once they reach Laltu, Manu is shocked to learn that Hardy never married out of love for her. When Hardy proposes to her, she dies.