The movie begins showing wizard Kaldorf expelling witch Drizelda from a village. Kaldorf allows Drizelda’s niece Athena to stay. The elf villagers fear she will turn out like her aunt because she keeps vermin (Jerry) and has an affection for cats (Tom). The cat and mouse are babies and Athena is only a young barefoot girl.
The film fast forwards to Tom and Jerry chasing each other, as they usually do, until they happen to come across a mysterious glowing egg. What neither of them know is that this egg was stolen from a very large, fire-breathing dragon. In a short time, a baby dragon named Puffy hatches from this egg and believes that Tom is his mother. However, Puffy’s real mother is angered that her baby is missing and wants him back, but before Tom and Jerry can even try to find her, a powerful witch named Drizelda captures Puffy, intending to use him for her own wicked plans. With the help of powerful allies and animal friends, Tom and Jerry must work together and fight tooth and claw to stop the witch and get Puffy back to his mother.