Louie the rat loves to make useful things out of not-so-useful things, but his inventions don't always turn out so useful. One day, he sees rats wearing fancy, stylish hats that aren't useful, so he decides to make some useful hats. He makes hats for warmth, shade, safety, and even bad hair days. No one wants any of his inventions, so he decides to never make anything again, but he gives away the useful hats to some rats in need on his way home. Soon, word spreads of his useful hats, and his business grows. But when the streets flood after a big rain, Louie finds a way to make his not-so-useful hats useful after all.