 
            When Monsieur Crauqual, the supervisor, is found hanging, all wonder why this rather rich person decided to kill himself. And when a pupil is found hanging too, François and his friends decide to investigate. They are certain there is a killer within the walls of Collège François 1er and determined to prevent him from going on running wild.
 
                        
                         
                        
                         
                        
                         
                        
                        