Geert is a graphic designer. At night he notices a small stain on one of the walls of his appartment. During the day time, the stain has disappeared, only to re-appear again the next night. But this time, it is larger. The stain has grown. When he tries to touch it, he is hit with a terrible head ache. The next day the stain has disappeared once again. Geert becomes obsessed by the stain.