Yes! Precure 5: Kagami no Kuni no Miracle Daibouken!

The five girls plus Coco, Nuts, and Milk all go to visit a castle-themed theme park, where they dress up as princes and princesses and go off to have a fun-filled day. However, Coco and Nuts end up kidnapped! The girls have to save them with the help of two inhabitants of the Mirror Country, Hidarin....