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.

Celeste finally discovers who her father's murderer is and puts in place a bold plan to trap him on New Year's Eve. At the same time, Rose breaks into the Countess Castle to save Gustave, risking everything in a clandestine operation. Arsène, meanwhile, is looking for a solution to live his forbidden love story.