Everywhere in the world graffiti, murals and tags proliferate. There are those who want to erase them, like the so-called "beautiful" volunteers, the defenders of immaculate walls, the guardians of the wall cleaning. But there are also those who want to protect them and maybe disconnect them, because they could have a market value. What is the stakes of this war? And above all, who will win it? The story of graffiti art in the context of the history of contemporary art, told by deconstructing the reasons of its adversaries, in the light of the social and cultural ferment that gives it meaning.