Underdog is shrunk by Simon's new evil device and is placed alongside Polly in a birdcage. Luckily, our hero's powers are still useful and they break out of the cage. Seeing that his shrinking of people with his trick flower is taking up too much time, Simon decides to put his shrinking water into a rainmaking machine. Simon and Cad return to the lab only to be tripped up by a trap set by Underdog and Polly. Simon reverses the trap, and catches the pair inside of a rat hole. An army of rats soon corners Polly and Underdog.