The protagonist is Pin, prematurely grown in the world of crime, that during the German occupation was the pander of his sister too, getting her the customers among the soldiers. One day, to prove his courage, he steals a gun to a German soldier and, exalted by the fact to possess it, he runs to hide it underground, in an unknown lane all crossed by cobwebs: sign of a nature not contaminated by the man yet. After having been captured by the Germans he escapes from jail and he meets a man of Dritto’s gang, an individualist partisan that doesn't have any conscience of class and that always acts with his head. In his gang Pin is at his ease: after all, for him, also the partisan war is an adventure as another. The Dritto seduces the cook’s wife and he, to take his revenge, sets fire to the camp.
Following these irregular events, the inspector Kim arrives in the field, a student that in that investigation takes conscience of the meaning of the partisan war, also realizing that the violence is in both the fronts: the partisan, however, fight to reconstruct a more correct and serene society. Pin doesn't think it this way: in fact, when the partisan Pelle passes to the part of the fascist, his dominant thought goes to the buried gun in the lane of the cobwebs, place that him same has revealed to Pelle. Gone soon on the place, he bitterly realizes that that angle of intact nature (the only uncontaminated thing in the world) has been devastated by Pelle. Pin desolate cries, because they have stolen him his gun and they have contaminated the only heaven that he possessed. However, returning home, he finds again his dear gun in his sister’s room. He takes back the weapon, he bloodily offends his sister, and he runs away in the street, after having finally understood his function of partisan and after having acquired a conscience of class. He returns with the partisan Cugino to the lane of the cobwebs to show him his small destroyed heaven, and both wishes that the kingdom of the nature can win on the violence and on the same anger of the men. But it is night and the fireflies issue intermittent flashes; marvelous beasts, if seen from far; repugnant too, if seen from near.