The rockstars of Pontypandy Mike and Elvis are busy practising for their big concert in the harbour. When Fireman Sam pops over to hear them play, however, he finds the pair during a heated argument! The band decides to split up, and Mike and Elvis must both find new ways to entertain the crowd at the concert - but it’s hard to learn a new skill or to find a replacement in time. When sparks start flying at the concert, it’s up to Fireman Sam and his trusty firefighting crew to save the day and help Mike and Elvis become friends again.