A murder case rocks a small town when Julien Monnier is found dead, stabbed near the cave dwellings known as "Les grottes du Régulus." An old book is found beside him. Grace, a police captain, is put in charge of the investigation and discovers similarities with a ten-year-old case: a 17-year-old girl, Sarah, had been found dead, also stabbed, in the same caves. Grâce calls on Alex, her childhood friend who has become an expert in old books. He had investigated Sarah's death when he was a police officer. Alex reluctantly revisits the past and agrees to help, partly to reconnect with Grâce, his lost love. Their reunion rekindles old feelings and painful memories linked to their separation. As the investigation progresses, the memories of the protagonists and suspects become intertwined. Grace and Alex relive their past, but are confronted with conflicting memories and unspoken words.
Shemss Audat
as Grâce Talbi
Antoine Hamel
as Alex Mercier
Philippe Caroit
as Jean-Marc Monnier
Sophie Accard
as Sybille
Benjamin Gaitet
as Julien Monnier
Sacha Vanbockestal
as Théodore
Romane Raffin-Delys
as Morgane
Amanda Lamb
as Sarah
Gaëlle Battut
as Elise
Orianne Schiele
as Constance
Eric Bougron
as Paul Vimon
Amélie Prévot
as Camille Vimon
