Do numbers really grow on trees? They do in Numeria where quirky creatures called Number Bugs feed on them -- Primalopes eat only prime numbers, the Oddapotamus only odd numbers, and so on. Enter 12-year-old Leon who falls through a space-time wormhole into this strange land. But there is trouble in Numeria. A greedy interloper is clear-cutting the forest to grow zeros, and with his robotic Buggetters, is intent on exterminating the Number Bugs. Suddenly Leon and his friends are in a battle for their lives.