Underdog and Polly are trapped in a rat hole, surrounded by a army of rats. Weakened from their run from Simon and Cad, Underdog needs to regain his superpowers with his Energy pill. Polly gives him his pill and our hero soon clobbers the rat army. Leaving the rat hole, Underdog and Polly new mission is to stop the two villains from shrinking everyone with Simon's rainmaking machine. But at this very moment, Simon and Cad have already set up the device- filled with Simon's evil fluid- on a hilltop overlooking the city. The Machine is already operating.