Despite being warned that kittens are monsters, Ember the Chihuahua (who still aims for world domination) agrees to babysit a family of kittens for three days after the mother cat offers him an army in return.
To accomplish her evil plan to flood the town, Bubbles the goldfish has assembled an army of fish hiding in the town pipes, and it is up to Ember the Chihuahua to overcome his fear of water and rally the other pets to stop Bubbles.