When Princess Sabrina is sent away from her family, the king and queen of Mulakating, she must hide away in a dull, working-class town, living undercover to keep her blue-blooded identity secret. A school trip to a museum in the big city promises to be a welcome escape from Sabrina's big fat lie of a life. But when the museum guide hands the students a map, Sabrina's most terrifying fears are realised: There's an exhibition on her home country, Mulakating, and its royal family - her family! Her deepest, darkest secret could be revealed! In one long, breathless race around the museum, the secret princess must call upon her devious Uncle Ernie, her dopey friend Charlie and even Awful Agatha to keep the class away from the shocking truth.