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.

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.