Ben Silverstein is sent to his grandfather's house in the dumpy town of Buttonville to spend the most boring vacation ever. But when Ben discovers a baby dragon, he and his new friend Pearl take it to the only place in town: Dr. Woo's Worm Hospital. But the kids soon discover that Dr. Woo's is not a worm hospital but actually a secret hospital for imaginary creatures. . . where something hairy waits for them.