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.

Celeste and Leon disagree and their couple weakens. Rose does not feel  confident with the Countess and decides to leave the castle. For his part, Arsène discovers huge debts in her father's legacy and decides to reconnect with her brother. Meanwhile, Leon realizes that a corrupt colleague could be linked to the investigation of Celeste's father.