When Gupi and her friends step through a mysterious wardrobe, they find themselves in a completely different world: a dark, gloomy, and colorless realm ruled by a grumpy king. The king has lost his joy and hasn't laughed for a long time. And because the king doesn't laugh, laughter is no longer heard anywhere in his kingdom. Gupi and her friends decide to do everything they can to make the king laugh again and bring joy back to his realm.