When Hannah gets her own pony, she hopes it will signal the beginning of her being successful at something - because until then, she has been pretty much hopeless at just about everything.

But enthusiastic and happy Spike, with his wayward mane and clownish and clumsy ways, cause the other girls at the riding school to despise and shun them both, and Hannah’s dream of success appears to be doomed. But Spike has a secret: his comic persona hides the fact that when there is danger, when courage and swift-thinking are needed, he changes into his alter-ego of Superpony - and when he does, Hannah morphs into Pony Girl! Together the duo save ponies from danger, fight crime and do whatever it takes to keep people and ponies from harm.

How can Hannah harness the confidence and inner strength she experiences when she is Pony Girl to make changes in her own life? And can she keep their superhero identities secret from the other girls at the riding school, who despise and ridicule them both?