L'Île Noire
Müller's first appearance is in "The Black Island" where he is in league with English and Scottish counterfeiters. He tries to send Tintin to his psychiatric clinic, but Tintin defeats him and Müller accidentally burns his own house. He and his henchman Ivan manage to recover some of the counterfeit money and fly away to the Black Island. Once there, Tintin knocks out and gags Müller, but he is subsequently released by his employer Puschov and the other members of the counterfeit gang. Müller is ultimately taken into custody.