Barney's friends are playing in Derek's backyard building a sand castle. When they wish they could visit a real castle Barney appears and takes them to a magical forest. They meet a friendly elf named Twynkle who likes to play games and make new friends. She shows them the road to the castle where they ride pretend horses and meet a real king! After taking care of the castle while the king goes fishing the kids are made princes and princesses of the kingdom.