The story revolves around two childhood friends Arjun (played by Ajay Devgan) and Mannu (played by Salman Khan) who have some music lineage in their family history. Arjun dreams of being on stage as a performer in the music industry, to live up to his grandfather's unfulfilled ambitions. Mannu however has little interest in his music tutor father's instruments and is content with remaining a child at heart with a simpleton attitude.
Through the course of the movie, Arjun diligently pursues his dream, at one point almost leaving an uncle who is his only family. He finally makes it to London which he believes is where he can successfully reach his ambitions.
Arjun creates a fledgling band with Zoheb and Wasim (Rannvijay Singh & Aditya Roy Kapoor respectively), two brothers who'd duped their relatives in Pakistan to travel to London in pursuit of their musical aspirations. He also brings aboard Priya (played by Asin), a music enthusiast from a conservative South Indian family. The other protagonist of the movie, Mannu is however shown at this stage to be trying to make his livelihood by playing as a wedding band performer at the village back in India.
Arjun eventually invites Mannu to London to complete his band contrary to his own belief that the latter can create competition within the band.
Upon forming the band, Mannu is shown to have musical talent and the qualities of an entertainer. He therefore becomes popular with the audiences with his unique style of performing. This is contrast to the earlier part of the film where Arjun struggles to captivate the attention of the crowd despite the music.
As hinted earlier in the movie, Arjun starts feeling envious of the rising success of Mannu. As a further extension of the jealousy, Arjun who is starting a budding relationship with Priya starts sensing that she is now smitten by Mannu. While the latter now starts a relationship with Priya, he does become the target of Arjun's frustrations and therefore he seeks to sabotage his career.
The band embarks on a three city tour spanning Paris, Rome and Amsterdam. Here Arjun deceives a naive Mannu into going on a rollercoaster ride of promiscuous sex and illicit drugs. As the three city tour concludes, the band heads to London to perform at Wembley Stadium in front of an audience estimated at 25,000, which is of significance since earlier in the movie, the viewer is told that Arjun's grandfather had failed before a similar audience.
In the moments leading up to the stage entrance, Mannu comes to senses and chooses the righteous path and supports his mate.