2x21 - Krypto the Superdog

While away at Summer Camp, Kevin overhears some beavers talking about conquering the humans. After following them, Kevin finds out that they are being led by alien beaver, named Buggy, who is helping them build weapons with the trees. After he is captured, he contact Krypto, who, along with Streaky, arrives to help. It's up to Krypto, Streaky, and Kevin expose Buggy's true identity to the beavers.