Emmy, their rapidly growing dragon, has become a real grouch, saying she's missing "something," and the cousins don't have a clue what that something is. Jesse and Daisy go online to ask Professor Andersson, their favorite dragon expert, for help and end up seeing him being kidnapped! The kidnapper is none other than Sadie Huffington, the girlfriend of their enemy, St. George the Dragon Slayer. She has hatched a wicked scheme to use the professor to both find St. George and capture Emmy. Now the dragon keepers and their dragon must storm Sadie's castle and rescue the professor from the witch and her pack of vicious dog-men!