Nazareth, a legendary rock group that in the 1970s held a privileged spot in the Top Ten charts along with the Rolling Stones, Sweet, Deep Purple, Led Zeppelin, Genesis. Founding members Dan McCafferty and Pete Agnew have known each other from the first days of school and have been playing music together for over 40 years. Even today, these rock “dinosaurs” from Scotland can fill up the concert halls and their music is still full of energy. Bio Illusion‘s documentary attempts to look into the background of this rock legend and uncover the roots of the band’s longevity and continued backing of its fans.