"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.

Twenty years after three teenagers disappeared in the wake of mysterious lights appearing above Phoenix, Arizona, unseen footage from that night has been discovered, chronicling the final hours of their fateful expedition.