All of France is shaken by brutal murders of women in Paris. Police are looking for a sadist armed with scissors. Suspicion falls on the local fool. But who is he really—a helpless, underdeveloped young man, or a cold-blooded killer and a natural actor? That is what former detective Kelvele and three unemployed historians from the “Rotten Shack” on Rue Challe… are trying to figure out.