Police captain Gwenaële Garrec is investigating about the discovery of a corpse on the beach of Saint-Malo. She tries to convince her temporary teammate, captain Eric Vautier, that their case is more complicated that it seems.

The corpse of a woman appears in a cave near the sea in Saint-Jean-de-Luz. Captain Marie Daguerre will investigate accompanied by the Commander Becker, a rough Parisian police that prove to be the father of the main suspect, in turn disappeared.

A dead body is found on the stairs leading to the sanctuary esplanade of the town of Rocamadour. Before being killed, he was apparently forced to undergo an expiatory pilgrimage as in the Middle Ages and to climb on his knees the 216 steps of the staircase. But what sin could this man have possibly committed to deserve such a sentence?