Jai Verma (Sidharth Malhotra) and Diya Kapoor (Katrina Kaif) are childhood sweethearts. Jai is a maths professor and Diya, an artist. While Jai hopes to get a fellowship at Cambridge University, Diya wishes to get married to her long-term boyfriend. Jai agrees to get married reluctantly but the thought of saat pheras and the billion rituals as well as the fear of weddings ending in divorces make him change his mind. Jai criticizes these meaningless rituals and talks negatively of his marriage. He tells Diya that he has other plans for his bright future and she may not be a part of it. She walks away heartbroken. Jai gets drunk and passes out only to wake up in Thailand on his honeymoon. He discovers that it’s been ten days since he got married to Diya. He has no memory of it at all. Next up, he wakes up in Cambridge, only to find his wife about to deliver their child. He discovers that it has been two years since his marriage. He realises he has been time travelling and has no control over it.
Next time he wakes up, he is a professor at Cambridge University, his dream job. It has been eighteen years since his marriage. To his horror, Jai realises that it is the day when he and Diya are divorced. Heartbroken, he returns home and pleads to return to the past to set things right.
Jai wakes up the next day, realizing he is in the past, seven years after his marriage. He juggles many priorities of his family and career. However Jai gives more priority to work and instead of going for Diya’s first art exhibition, he goes to his friend Chitra’s (Sayani Gupta) place to help her with her breakup. Chitra tries to have an affair with Jai. Believing it to be the cause of his divorce,Jai hastily returns home, but his family is unhappy with him.