Plot synopsis: Inexpensive, expressive, nomadic, the guitar almost merges with the body of its musician to turn into a formidable weapon of protest. Brandished, swung, even burned, she carries the voice of the fight against oppression. From Woody Guthrie to Jimi Hendrix via Bob Dylan, the fascinating story of the musical rebellion is told here through the story of his sword. Blues, punk rock, rock'n'roll,... All genres are in the spotlight to tell the tumultuous epic, intimately linked to the history of American protest, of the most played instrument in the world. A poignant and moving documentary in the testimonies of its icons and most faithful servants: Wayne Kramer (MC5), Keziah Jones, Lee Ranaldo (Sonic Youth), Judy Collins and Clementine Creevy (Cherry Glazerr).