A group of musicians discovers in an old LP record a musical work from more than 40 years ago, which tells the story of a Riojan caudillo. They decide to remake this album and begin to summon musicians and interpreters to renovate the original versions.

Rodrigo Díaz de Vivar, whom History knows as El Cid Campeador, is an essential figure to understand the Middle Ages. His legend has endured throughout the centuries to become a myth. In this documentary we will discover his character as a military leader, a mercenary or a undefeated hero in hundred battles, but also as the man, with his virtues but also with his defects.