An Austrian prince hatches a plan to keep his rival, the Russian czar, busy by keeping him surrounded by beautiful women and away from the negotiating table. The Czar, however, has his own plan—he hires a man who is his exact double to impersonate him and confuse the Austrians by appearing to be everywhere at once. In addition, both the Czar and his double fall for the same woman.

Mary Poppins returns to the Banks family and helps them evade grave dangers by taking them on magical, musical adventures.