Spinal Tap, England's loudest and most punctual band, reunite following a 15-year hiatus for one final concert.

Spinal Tap, an aging rock band from England, embarks on a North American tour that is documented by film director Marty DiBergi. As they promote their new record and face various mishaps and setbacks, the band's popularity begins to decline. Internal conflicts and hilarious incidents ensue, but they ultimately find redemption when they discover that their song has become a hit in Japan.

The mockumentary follows the return of the legendary rock band Spinal Tap as they reunite for a new tour. With their signature style of improvisation and hilarious antics, the band navigates the challenges of the music industry while providing plenty of laughs along the way.