A woman with a metal plate in her head from a childhood car accident embarks on a bizarre journey, bringing her into contact with a firefighter who's reunited with his missing son after 10 years.

In Paris, many citizens go to the precinct after the doors of their apartments have been sprayed with a 4 and the letters "clt". When a dweller is found mysteriously dead in his apartment, Detective Jean-Baptiste Adamsberg and his partner Danglard investigate...