Chris Cole, portrayed by Mark Wahlberg, is an ardent fan of the legendary 80s heavy metal band Steel Dragon. During the day, he earns his living as a photocopier technician, but by night, he steps into the spotlight as the lead singer of a tribute band named Blood Pollution, which draws its name from a Steel Dragon track.
The inner turmoil within Steel Dragon leads to the dismissal of their lead vocalist, Bobby Beers (played by Jason Flemyng), prompting the band to seek a new singer. Meanwhile, Chris faces his own challenges with his Blood Pollution bandmates, notably his guitarist Rob Malcolm (Timothy Olyphant). Tensions boil over during a live show when Chris sabotages Rob's amplifier, resulting in a public altercation on stage. Following this incident, Chris discovers that he has been ousted from Blood Pollution, replaced by his rival, the former frontman of another tribute band. Rob points out Chris' failure to innovate musically, suggesting he is overly reliant on duplicating Steel Dragon's work.
An unexpected twist occurs when Chris receives a call from Kurt Cuddy, Steel Dragon's founder and rhythm guitarist (played by Dominic West), offering him an audition after seeing a tape of Blood Pollution in action. Initially skeptical, Chris soon realizes this is a genuine opportunity and eagerly agrees to the audition. At the studio, he learns about Bobby Beers' controversial departure and captivates the band with his rendition of "We All Die Young," a song featured in the film.
Embracing his new identity as "Izzy," Chris experiences the whirlwind of fame and success that comes with joining Steel Dragon. The band embarks on a massive tour, with their manager, Mats (Timothy Spall), providing guidance through the rock star lifestyle. However, the toll of this newfound fame strains his relationship with his girlfriend, Emily Poule, played by Jennifer Aniston. Emily ultimately decides not to continue supporting him during the tour, although they agree to reconnect in Seattle.
As the tour reaches Seattle, Emily visits Chris in hopes of rekindling their connection, but she is met with his intoxicated disregard and the chaos that surrounds him. Faced with the harsh realities of his lifestyle, Emily leaves, heartbroken by his actions.
After the tour concludes, Chris attempts to contribute creatively during recording sessions for Steel Dragon's next album, only to find his ideas dismissed by the band, which insists on sticking to their established sound. This leads to a confrontation with Mats, where Chris expresses his fear of losing control over his life. A pivotal moment occurs during a concert when he invites a fan named Mike on stage to share the spotlight. This experience brings clarity, prompting Chris to resign from the band and abandon the rock star facade.
Returning to his roots, Chris rekindles his passion for music by forming a coffee-house rock band with his old friend Rob. He stumbles upon Emily, who now works at a coffee shop, but is hesitant to approach her at first. However, fate intervenes when Emily discovers a flyer for his band. In a heartwarming conclusion, Chris performs at a bar where Emily enters, and they finally reconcile with a kiss as he performs his original song "Colorful," marking a new beginning for them both.
