Leon accepts that Céleste will accompany him to Saint-Loup to investigate the murder of his father. Octave and Arsène, in search of funds for their electric motor project, organize a clandestine boxing fight. Rose,who thought he knew Charles, discovered his true identity.

As she discovers inconsistencies about her father's death, Celeste is convinced that it is a murder and not a suicide. Rose, caught up in her past, is unmasked by Charles' mother. Arsène, helped by Octave, is trying to break a speed record to save his project and find investors.

While interrogating a former teacher from Saint Loup, Céleste discovers a new suspect who could be linked to the murder of her father. A victim of prejudice, Arsène is about to lose a major contract. Rose learns very good news and is looking forward to writing to Charles to announce.