1986, West Berlin. Five resettled members of the Weimar underground punk scene in East Germany plan an exceptional art project that they call White Line. They will paint a white line that encircles the west side of the Berlin Wall as a political statement to the normalization of the existence of the Wall in the West. While the concrete Wall remained gray and austere on the east side, the west side had been colorfully painted by artists, turning it into a tourist attraction. The five artists believe that this obscures the meaning of the Wall as a deadly and dangerous border that divides a city and a country. The documentary tries to reconstruct this unusual art project that was interrupted by East German border guards who took one of the artists through an almost invisible Wall door to the East where he was imprisoned. The artists hadn't considered that the actual border ran about 9-13 ft on East German territory, placing the "west side" of the Wall on GDR soil. But how did the East German guards know about their project? Almost three decades later, the artists find out that one of them was a state security informant.