The English heavy metal band Spinal Tap embarks on their biggest tour into the United States to date to promote their new album "Smell the Glove". The tour is so huge that it's attracted the attention of documentary filmmaker Marti DeBergi, who decides to make a movie about the legendary band's trek across America. But as the documentary goes along, Spinal Tap sees their audiences dwindle from selling out huge arenas to going to play at charity benefits, and eventually playing private parties where no one pays attention to their music. Their new album drops and it's decently reviewed by critics, but the record stores have a huge problem with the sexist overtones of the album's cover, causing a loss into sales. However, a series of incidents that constantly shoot themselves in the foot - whether it's a minuscule Stonehenge monument, a stage prop malfunction, or a simple two word review of an album - keep preventing the band from enjoying the success they deserve. But how long can they keep playing to 11? And will they find the audience that suits them?