Back in Brittany, Captain Morgane Ledantec is confronted with the discovery of human bones after the fall of a sacred oak during a storm. The victim was a follower of druidism which Morgane was introduced to as a teenager by her godmother.

Alex, whose singing career can't manage to succeed, accepts a strange job : to make a pensionner choir sing nursery rhymes. She finds out a bunch of out of control old people who dream of singing rock and roll music ! Her mission will be more complicated than expected...

Nine years after little Marina went missing along a highway near Dunkerque, a young woman with amnesia who looks just like her reappears in practically the same spot.

Beneath her eccentric appearance, Captain Marleau is a formidable detective. Her Sherlock Holmes deerstalker cap, her character, her unusual appearance, her humor, her unpredictable behavior--Captain Marleau is not your average gendarme. She never rushes an investigation; she becomes the investigation and relentlessly pursues the suspects.

Between 1978 and 1979, the inhabitants of the Oise are in fear of a maniac who kills several hitchhikers and escape the police. He was then dubbed "the killer of the Oise" is actually a shy young policeman who will investigate his own murder, only to lose control of the situation.

French adaptations of the stories by Agatha Christie.