Alice (or you can give her any other name you like), the Princess of Hearts, rescues a mysterious stranger who collapsed at the gates of their castle during a terrible storm -- and he's very mysterious indeed, because whatever happened that got him lost was apparently bad enough to also give him amnesia. He says his name is Eduard, and his clothing looks like it came from the Kingdom of Clubs, but other than that, he doesn't remember anything. As she nurses him back to health, they fall in love. However, the King and Queen of Hearts decree that she cannot marry him unless he proves through a test that he is royalty (not really a surprise: he isn't). For some weird reason, that test involves a giant pile of mattresses and a pea.

Bonus: Germany Mochi saves the day.