Princess Margaret dwells in a castle within a cloud kingdom reached by climbing a giant beanstalk. Her parents, the former monarchs, were murdered by the witch Madame Hecuba, who now commands the castle. Enchanted by Hecuba’s spell, Margaret exists in a trance, believing herself blissfully content and fated to wed Hecuba’s son, the giant Tulip. This enchantment visibly manifests as vacant, dull blue eyes—masking her natural brown irises—and a tendency to appear barefoot.

She vocalizes her artificial happiness through the song "Nobody’s Happier Than I," a direct result of the spell. Under its influence, she greets visitors like Jack and his dog Crosby with initial warmth yet emotional detachment, inadvertently introducing Jack to Madame Hecuba and enabling the witch’s scheme to imprison him.

Hecuba must renew the enchantment daily to sustain control. Margaret’s true self emerges only when the spell breaks via a kiss from someone "truly brave"—delivered by Jack during her coerced wedding ceremony to Tulip. Freed, she instantly identifies Hecuba as her parents’ killer and recoils from Tulip with terror and disgust.

Following Hecuba’s defeat and the undoing of the castle’s curses, Margaret reclaims her throne as ruler. The castle’s inhabitants, previously transformed into mice by Hecuba, revert to human form. Margaret continues her reign in the cloud kingdom after Jack descends and severs the beanstalk.