Return to Numberland is a special.
It's been a while since the events of Journey to Numberland that Team Umizoomi has seen The King of Numbers and Zilch. One day Team Umizoomi gets an invitation from The King of Numbers to visit him for a surprise. The surprise is Zilch becoming the Prince of Numbers! Zilch doesn't know how to be a prince, and frankly he's quite worried that he won't be a good prince. But when a troll sorceress by the name of Vienna comes to claim the title of Prince of Numbers, Zilch must pull himself together and show Vienna that he is the rightful prince. And with the help of Team Umizoomi, Zilch just might be able to learn what it means to be a prince.
- Ziclh is the only antagonist to remain good in his second appearance.