The film is about four friends, Aditya, Joe, Rob and Kedar aka KD ("Killer Drummer") who start a rock band and struggle to make it big in the rock world. Two parallel plotlines follow them at different times during their lives. They are both woven together at strategic points, which lends the film its much-praised nostalgic quality.

The first of the two centres on the four in their early twenties, when they are young, wild and carefree, and their main focuses in life are music and friendship. During this time, they create a band called 'Magik', and meet to practise regularly in an old basement.

A competition is announced, specifically for Indian rock bands, to be organised by Channel V, where the winner will be offered a contract for an album and at least one music video. The band need money for new instruments and they earn it by playing old Hindi songs at random Dandiya parties, even though it kills them to do so. They enter the competition and win, though it eventually turns out be their downfall.

They are forced to make a number of compromises while signing the contract, which creates some tension within the band. Joe feels the most slighted as his song is not included (making way for a remix of a random wedding song to capitalise on the upcoming "wedding season") and his girlfriend, Debbie (for whom he had written the song), an aspiring fashion designer, is refused the chance of being the band's stylist. Later, when the cameramen focus solely on Aditya during the filming of the music video, Joe confronts him, accusing him of trying to take over the band. Things get worse when the film director rudely intervenes, and Joe lashes out at both him and Aditya, before marching out of the studio with Debbie.

Aditya, who had failed to notice anything much was amiss, is shocked and decides to leave as well. He packs his stuff, writes a note breaking up with his girlfriend, and leaves for Delhi. In this way, Magik disbands and its members, once the closest of friends, become estranged from each other.

The second plotline follows the band members ten years later. Aditya is a high-powered executive in an investment banking firm. He is cold, impersonal and shuttered, and his wife Sakshi feels as though she doesn't know her husband at all. She plans a surprise birthday party for him and goes to buy him a watch. KD, who has joined his dad's jewellery business and who owns the shop, overhears Sakshi talking about Aditya, and wondering if its his old friend, asks her to mention him to Aditya. Aditya, who has not told Sakshi anything about his past, denies knowing anyone called KD. Sakshi waves off the incident until she finds a box hidden in the closet with the lyrics of a song, a guitar pick and candid pictures and videos of Magik. Seeing KD in them, she contacts him and asks him to invite the rest of the band to Aditya's birthday party.

KD meets up with Rob, who makes a living composing jingles for advertisements. They go together to invite Joe, who is largely unemployed earning a buck or two performing at weddings where nobody pays attention to the music. He has an eight-year old son, and the family is largely supported by Debbie, whom he has married, and who runs his family's fish business. Debbie, who still holds a grudge against the band for what she perceives as their ill-treatment of Joe, sends them away and forbids Joe from staying in touch with them.

At the party, Rob and KD plan a reunion at their old rehearsal hall, the basement, though Aditya, who wasn't too pleased seeing his friends again, is not too enthused. He confesses to Sakshi after the party that she should not have invited them. She retorts by telling him that all she wanted was to see him happy, especially now that they are having a child (Sakshi is pregnant). She leaves for her mother's house, saying that she cannot have a relationship anymore with a man who won't let her in.

The next day, Aditya goes to Sakshi's friend, Devika, for advice. She tells him to stop running away from his past, so he decides to meet his ex-bandmates at the basement. Joe is also there. He shakes hands with Aditya, wishes him a belated birthday and the band's differences seem to have been resolved. They start practising regularly at Aditya's house. Learning about this, Sakshi also returns home.

Soon, another contest hosted by Channel [V] is announced, and at Rob's insistence, they enter themselves. Debbie, who is adamant Joe get a regular job, arranges for him a guitar-playing job on a cruise liner, but the ship is to sail on the same day as the contest. When it is discovered that Rob has a brain tumour and his last wish is to perform with Magik one last time, Joe's choice becomes very difficult. Debbie insists that he go for the job, especially as their financial situation is so bad and they have a son to bring up. The contest is aired on the radio, and while Joe is in the taxi on the way to the airport with his family, he hears Magik play the song he wrote for Debbie so long ago, and dedicate it to him. He leaves the taxi and goes to the concert, reaching just as the song ends. On seeing him, the band immediately perform another song, which turns out to be their last together onstage.

In a short epilogue, it is revealed that Sakshi gives birth to a baby boy, who is named Rob after their friend who died two months after their final performance. Devika, Sakshi's friend, gets into a relationship with KD, who starts a record company with Joe, which promotes new talent. Debbie pursues her dream of being a fashion designer. The band members and their families meet at least once a week.