Jonas Jones and his little dog Scraps first encounter Lizzie Linnet on their way to market. She's not very friendly to them, but Jonas knows she needs their help. Lizzie's hiding something, and Jonas is sure it has something to do with Lizzie's part in Madam Mesmer's Marvellous Medicine Show, conning people into buying Octodius Ollett's mysterious potions. Lizzie knows she must escape, but she can't leave her only friends, Dobbin and Bray the donkeys. And even if she did get away, where would she go...?