A castrated corpse that opens its eyes during the autopsy. A mobile phone ringing in the body of a young drug addict who died from unexplained burns. Despite his long service in the area of Saint-Denis, police officer Victor Cost is preparing for the worst.

And a stack of anonymous letters that reveal the path to a mysterious folder named "Code 93"...

A journey that will make Cost cross the boundaries of the peripheral road and logic, from the high Parisian circles to the degraded neighborhoods...