The heroes are actors and they share a private joke it just shows to go you

"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.