Sienna didn't know she was a princess until the day her anxious but helpful Lady-in-Waiting, Felicity Fluttertung, knocked excitedly on her door, whisking her (and her overly-sensitive teddy bear Rufus) away once a year, on her birthday, to the land of Humbertia. Once Princess Sienna's coronation is finished, she is free to explore the land, the sea and the air...and she does. Swimming with the local mermaid, soaring above the land in a hovercraft, finding the magical spots of the kingdom, meeting new friends and sneaking Rufus into royal events which otherwise adhere to the "No Bears Allowed" policy are just some of Princess Sienna's adventures.