The document describes a concert by Deep Purple that was interrupted by a fire at the casino in Montreux, Switzerland on December 21, 1971. Frank Zappa and the Mothers were recording at the casino when someone set it on fire with a flare gun. This forced Deep Purple and the others to find another location to record, inspiring the song "Smoke on the Water." They ended up recording at the empty Grand Hotel, using a mobile recording unit, but time was running out in Switzerland.