In the novel The Mystery of the Blue Train, Mirelle is a Parisian dancer at the Parthenon. She is the lover of Derek Kettering. She is described as a "beautifully made woman. Her face, beneath its mask of yellow, had a bizarre charm of its own". Her eyes are big and black.
Mirelle has been in the public eye for about two and half years, after being started by a French duke. According to Joseph Aarons, there is always money available to back her, but he has heard that she is "a terror to deal with", because of what he refers to as temperament.
She lives in an Eastern themed flat in Paris. In her flat, there is a divan, with "an incredible number of cushions, all in varying shades of amber". These cushions harmonize with the "yellow ochre" of Mirelle's complexion. There is also a piano, on which Claud Ambrose plays his operatic setting of Ibsen's Peer Gynt for Mirelle. Mirelle is actually uninterested in Ambrose's work, seeing it only as a "unique opportunity for her own presentation as Anitra". She plans to put "all the passion of the desert" into the dance, and to perform it "hung over with jewels".
Mirelle loves jewels, and tells Derek that jewels "say something" to her. She tells him about a black pearl she saw in Bond Street, and about Rufus Van Aldin's purchase of Heart of Fire. According to her, Heart of Fire is the most wonderful ruby in the world, and should belong to a woman like her.
Derek tells Mirelle that his wife is going to divorce him, and Mirelle expresses the opinion that it is foolish to do so. Derek asks if she will stick to him even if he is financially ruined, and she says that she adores him, but she is not made to be poor.
Mirelle also expresses the opinion that if Ruth Kettering were to die, this would be a solution to their problems, because Derek would inherit all her money. However, she decides that they must not "dwell on possibilities", and so tells Derek that Ruth must give up the idea of divorce. She also tells him that Ruth is going to meet the Comte de la Roche in Paris.
Mirelle later travels to Nice on the Blue Train. In Nice, she speaks to Derek, telling him that she knows what he has done for her, and that their life together will be wonderful. When Derek tells her that he is finished with her, she becomes very angry.
Mirelle goes to see the Comte de la Roche, and tells him that the police suspect him of murdering Ruth, but that she knows that Derek is the murderer. She tells him to go to the police with this information.
Mirelle later tells the police that she saw Derek come out of his wife's compartment, just before the Blue Train reached Lyons. When she found out that Ruth was dead when the train left Lyons, she knew that Derek had killed her. At that time, she did not go to the police because she did not want to betray her lover. However, now that he had broken things off with her, and had fallen in love with another woman, she felt differently.
When Poirot asks Mirelle how she knew that Ruth was dead when the train left Lyons, she says that someone had told her. It is later revealed that Mirelle had entered Ruth's compartment after the train left Lyons, and found her dead.
When Poirot asks if she found what she wanted in Ruth's compartment, or if someone else had been there first, Mirelle screams that she will answer no more questions. She tears herself away from Poirot's grasp, and flings herself to the ground, screaming and sobbing.
At the end of the novel, Mirelle has begun a relationship with a Greek ex-Minister, and he has given her thr Heart of Fire. She wears it on a platinum chain around her neck, and tells people that it has a curse on it.
Portrayals[]
In the 2005 ITV adaptation of The Mystery of the Blue Train, Mirelle is portrayed by actress Josette Simon. Here she is also given a last name of "Milesi".
In this adaptation, her plot role and backstory is different. She is not Derek Kettering's lover. Here she is the lover of Rufus Van Aldin. He sent her on board the Blue Train in order to compromise Derek and try to gather evidence to establish grounds for Ruth Kettering to divorce him. This, however, does not work as she discovers that Derek (in this adaptation at least) is genuinely in love with Ruth.
After the murder of Ruth Kettering, Poirot searches her compartment and finds among other things, a cigarette lighter and the last page of a letter to Rufus Van Aldin from one Sister Rosalie. Later he witnesses a strange incident at the Villa Marguerite where Mirelle attacks Rufus Van Aldin in anger for something he had done. When Poirot makes his way to Sister Rosalie's convent in Nice, he meets Rufus Van Aldin who arrives just after him. They meet one Sister Dolores who Van Aldin tells him is his wife, now mentally unstable. Sister Dolores tells them a strange story of her daughter Ruth visiting her and bringing her some flowers which she shows them. This cannot be because Ruth had already been murdered before she arrived at Nice.
While Van Aldin thinks Dolores is deluded, Poirot pieces some of the pieces together and confronts Mirelle. She admits that the cigarette lighter is hers. She had gone to Ruths compartment (she had already been killed) because she wanted to "look at her things". She also found the letter from Sister Rosalie (Poirot saw her reading a piece of paper in the dining car). She then went to visit Sister Dolores because she wanted to what her own eventual fate would be if she went on to become Van Aldin's wife. Dolores had been delusional and thought Mirelle was her daughter Ruth. Mirelle thought it would be cruel to correct this belief.