"The Man Who Did Not Exist"

A man collapses lifeless on a bus. Covered in blood, the corpse does not bear any wounds. Death could have been caused by an extremely contagious disease.

A woman is found murdered. All the DNA evidence collected at the crime scene converges on a suspect, in prison at the time of the crime. Astrid and Raphaëlle quickly understand that they must be dealing with a serial killer.