"This Is Spinal Tap" shines a light on the self-contained universe of a metal band struggling to get back on the charts, including everything from its complicated history of ups and downs, gold albums, name changes and undersold concert dates, along with the full host of requisite groupies, promoters, hangers-on and historians, sessions, release events and those special behind-the-scenes moments that keep it all real.

Marty DiBergi drops everything to document Spinal Tap’s final concert, as a chance to redeem himself after the band’s disappointment with his first film.