The Adventures of Tintin #11: The Secret of the Unicorn

There is an amazing epidemic of wallet-snatchings around Brussels. Thomson and Thompson - who, during the course of the story, eventually lose their wallets by the dozens to the thief - look for the culprit at the Old Street Market where they meet Tintin. Tintin buys a boat model of an old ship for Captain Haddock, but, as he does, two men try to haggle it off him. But why?..