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 the case and discover that plague may have killed the victim. Meanwhile, in the center of Paris, the former actor Joss Le Guern survives reading advertisements in a square for the public; when he receives weird messages about an outbreak of plague that is coming to Paris, the former professor Hervé Decambrais requests the warnings and goes to the library to research the meaning of the text, where he meets Adamsberg. Together they find that a maniac is killing people using flees contaminated by rats and spreading the disease in the city; without any clue, the police force do not have how to avoid the panic in Paris.

After five years in jail, Leila is free again. Yannick, a young athlete, recently lost his sight in a car crash. The only discipline in which he can compete is running, but he must race tethered to a guide. Before she went to prison, Leila was an elite athlete. She will be Yannick's eyes. Leila keeps quiet about her past. Sick of the sympathy of his family and friends, Yannick welcomes her silence. Training and preparing to race helps them both rebuild their lives. There are past events that won't let go, and present feelings and emotions that bring upheaval and a new direction. But you have to keep running and battling, down the straight to the line.