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.

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?

A police captain learns that his ailing father could be connected to a murder at Rouen Abbey.