How big is YOUR imagination? Penny has a huge imagination and loves to read books! She has just discovered a new book about cowgirls. With the help of her best friends, Cassandra and Jack, Penny wants to become the best cowgirl EVER. But Penny doesn't have one of the most important things she needs: a horse! So, she and her friends head to the zoo to find the perfect animal to help Penny become a cowgirl.