After Mr. Sweet contacts Tarot and his friends, Lulli discovers that Winthrop’s former assistant Thalia Smith is involved in the theft. She takes the doctor to see Brigadier Connaught, but before they can reach him they are both captured by Thalia and her brother Dalbiac, and taken to their windmill hideout. Thalia plans to sell off the stolen consignment of ‘H23’, and plans to demonstrate its effects to her buyers by using the gas on Lulli and Winthrop.