Milli and Geo are sent to Umi City to live under temporary care. Along the way, the sibiling encounter a robot named Bot and a villian name Machiro whose determined to turn Umi City into his own personal kingdom. When Machiro kidnaps the children, it's up to Bot to save them.
A mayan princess named Kisa is banished to the forest by her wicked, jealous sister Quazula. Quazula then covers the entire land in a thick fog to prevent anyone from finding the princess. Team Umizoomi goes to find Princess Kisa and bring her back to her rightful throne, but not if Quazula and her minions have anything to say about it!
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 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.