Crystal Mother

Kaito and Aoko are on a luxury train with the Queen of Ingram, her son, and the Principality of Ingram's Crystal Mother, a huge topaz that may contain the Pandora jewel. The queen has the real jewel cleverly hidden, though, making it a challenge for Kaito/Kid to find it before the train reaches Osaka. On top of that, he's got competition, as there's a Snake on the train!