Summer 2006: The Swiss heavy metal band Celtic Frost hasn't given a concert in sixteen years. Now they are standing on the stage of the largest heavy metal festival in the world in Wacken, Germany. Sixty thousand fans are celebrating the return of a legend. Celtic Frost, one of the few world-famous Swiss bands, is back! This documentary film accompanies the band on their comeback tour through Europe, the U.S.A. and Japan. It is a journey to the heart of darkness, of extreme metal and the band members' attempt to live up to their own legend.