Mirabelle is special because she is different. Her mom is a witch and her dad is a fairy, and she loves to cause magical mischief. So, her parents' garden party picnic seems to be the perfect opportunity to play some pranks on her annoying brother, Wilbur. But when Mirabelle gets caught putting frog eggs in Wilbur's drink, she is sent inside. It's so unfair! Why does she have to miss the party? Then she gets a brilliant idea: If she uses a shrinking potion on herself, she'll be too small to be seen, so she can enjoy the party! But Mirabelle is about to discover that the garden looks a bit more dangerous when you're as tall as a blade of grass. Have her antics gone too far this time . . . ?