save Lafitte, but the masked murderer got there first. Vidocq pursued the murderer, who seemed to possess magical powers and a mask made from a strange reflective surface. Boisset's investigation leads him to Sylvia, the brothel manager, a journalist named Froissard who is investigating the masked murderer, and Marine Lafitte, wife of Ernest. They reveal that Lafitte, Belmont and Veraldi were narcissists, committed to preventing death by aging. A man with a mirror mask, called the Alchemist, offered them an elixir of eternal youth in return for their cooperation in capturing young maidens for his experiments. The three rich men went along, but later stopped cooperating due to a sense of guilt, so the Alchemist killed them. After Boisset leaves, the Alchemist arrives, killing Froissard and Marine. Boisset's investigation attracts the attention of Tauzet, who notices that the Alchemist is disposing of witnesses, and fears Boisset is next. Boisset sneaks in to retrieve Vidocq's notes, where he encounters Lautrennes and Tauzet. Lautrennes attempts to arrest Boisset, but the journalist escapes. The notes reveal that Vidocq found the Alchemist's lab, where he was using the maidens' blood to create a magic substance for his mask, which grants eternal youth by sucking the souls out of his victims. The Alchemist arrived and attacked Vidocq, who managed to take a piece from the Alchemist's mask before the killer escaped. Vidocq's final note states that the Alchemist would need someone to manufacture the mirrored mask, leading him to the glass factory. Boisset, Nimier and Preah head to the factory, ushered by an artisan, and closely trailed by both Tauzet and Lautrennes. Just as Boisset declares there are no more leads and witnesses, the artisan removes his prosthetic, revealing himself to be Vidocq. It turns out Vidocq had jumped into a secret hole in the furnace wall, which he saw in the reflection of the mirror mask before the Alchemist's reveal to be Boisset himself. Vidocq then admits to faking his own death simply to let Boisset's guard down, as he knows the Alchemist would destroy all clues and witnesses through any means necessary. With his cover blown, Boisset lets out a monstrous roar and dons the Alchemist's mirror mask. Nimier opens fire, but is killed as the Alchemist magically reflects the bullets back at him. Vidocq pursues the Alchemist into a hall of mirrors, where he forces the Alchemist to look into a mirror