Frisky princess Marie Christine, known as Mitzi (Janet Gaynor) passes herself off as a manicurist, and falls in love with Karl (Henry Garat), a delicatessen worker, though he's really a lieutenant in Mitzi's army. Back at the palace, the Prime Minister (C. Aubrey Smith) tells Mitzi her betrothal to a prince she's never met will be announced. Unaware of the truth, the Prime Minister secretly tries to convince Karl to make Mitzi forget the delicatessen man, while Mitzi, to test his love, tells Karl she's jealous of the princess. More romantic/comic complications ensue.