Celeste LaTour was the princess of a gypsy tribe which was once led by her mother, Marie LaTour, who was a notorious villainous werewolf. Marie prowled and killed various animals, and later killed her husband (Celeste's father), George LaTour, after George found out about Marie's heel persona. As the film also revealed, Celeste was also a werewolf, having inherited the trait from her mother, and she was informed by Yan Spavero--the janitor at the LaTour Museum--that Dr. Charles Morris was writing a book about Marie.
In order to prevent "outsiders" from learing the truth about her mother, Celeste went to the museum and killed Dr. Morris in her wolf form. Detectives suspected Elsa Chauvet, Dr. Morris' Transylvanian-born assistant, of the murder, and after Yan's prints were found, it was also suspected that the pair was in cahoots. Yan's return to the gypsy camp was met with verbal lashing from Celeste, who later transformed and killed Yan.
Celeste later made a public arrival at the museum, giving an interview before meeting Robert Morris, Charles' son and Elsa's boyfriend. Both Elsa and Robert were wary regarding Celeste, but during their meeting, the villainess used her power and feminine wiles to mesmerize Robert into being convinced that Celeste and her tribe were incapable of killing his father. Robert's demeanor was met with astonishment from Elsa, who later gazed at Marie's photo and attempted to uncover her and Celeste's sinister secrets. At that moment, the evil Celeste arrived and placed Elsa in a trance, referring to Elsa as her sister and stating that she would be the daughter of a werewolf like her.
Celeste's powers caused Elsa to suddenly give a false confession to killing her father, though Robert figured out that Elsa's confession was Celeste's doing. The villainess pursued the detectives in her werewolf form, sparking a confrontation that saw Celeste shot by the group before appearing to Robert and Elsa. Celeste attempted to order Elsa to kill Robert, only for Robert to successfully convince Elsa to use her own free will, after which Celeste transformed and lunged after Robert. The detectives returned and shot Celeste to death, and watched as Celeste reverted to her human form, while Elsa was freed from Celeste's trance.