With the help of a mysterious figure, the Happy Babies find the Dragon Cave on the island. However, Huanhuan and Lele are injured by the dragon, while Doudou is swallowed whole. Huanhuan and Lele are rescued by the mysterious figure, who guides them—Huanhuan upgrades his equipment, and Lele masters fire-based techniques. They battle the dragon once more, and the dragon spits out Doudou and returns the treasure book. Yet the book does not produce any magical power, and the Happy Babies embark on a new journey. This season is a remake of the 2013 version of "Happy City 2."