Metallica have been almost instrumental in moving the genre of metal forward, and over more than 27 years they have mutated, changed and developed while so many of their contemporaries have remained stuck in the proverbial rut! This documentary film traces the complete history of Metallica, from their earliest incarnation as one of the "big 4" of Thrash-Metal, through the tragic death of Cliff Burton in the mid-1980s to the mega-stardom they enjoy today. And with the aid of interviews with band members, friends, colleagues and associates and using archive footage and location material, rare photographs, commentary from the finest metal journalists and a host of other features, it gets to the heart of what made this extraordinary group the primal force they have become.