The discovery of Patrick and Laura's affair directs suspicions towards Armelle, who could have wanted to eliminate her rival. But the latter is innocent: she spent the night of the murder in the hospital at Lucas' bedside. While the investigation is at an impasse, Fanny is faced with a realization as terrible as it is clear: what if she was the one who killed Laura? To find out, Fanny, contrary to her scientific convictions, asks her mother to prepare a drink for her so that she can finally try to recover her memory...