Rare performance clips, exclusive interviews and behind-the-scenes footage combine to create a comprehensive review of Pantera -- the highly influential heavy metal band that lost its virtuosic guitarist, Dimebag Darrell, in 2004. The band's members, producer Sterling Winfield, Dimebag's biographer, Zac Crain, Metal Hammer editor Alexander Milas and more reflect on Pantera's reign as thrash metal royalty.