Four young musicians are en route to a televised concert in London, navigating the thrills and challenges of sudden fame. Amid the clamor of screaming fans and a hectic travel schedule, they humorously deal with the press, mischievous escapades, and the demands of their manager and TV director. Their journey is further complicated by the unexpected presence of one member's mischievous grandfather, whose antics add to the chaos and tension within the group.

As the day progresses, the quartet must rehearse, perform, and fulfill their roles as pop culture icons, all while trying to stay true to themselves and their music. Multiple attempts at a moment's peace are comically thwarted by obsessive fans, overzealous television staff, and even the police, reflecting the surreal nature of their fame. The band's camaraderie and quick wit are put to the test as they strive to make it to their performance on time, amidst the delightful pandemonium that surrounds them.