The movie starts with varun dhawan showing his class.He comes in love with kirti and flirts with her. As the time passed, they both loved each other.
Varun’s brother i.e. sharukh khan went to meet kirti’s sister and when they saw each others face, they were not agreed with the relationship.
Now the reason was shown in flashback . 15 years ago sharukh khan was known as kali and was a don.He came in love with kajol . afterwords he came to knew that kajol was from the opposite gang.they began hating each other. After 15 years they realised their mistake and agreed for the marriage