In the magical Kingdom of Wrenly, Prince Lucas befriends Clara, the daughter of a village dressmaker, breaking royal rules about who he can play with. When Clara's mother loses her precious rainbow stone—a family heirloom that brings good luck—Lucas promises to help find it. Their search becomes a secret adventure across the kingdom, from the forests of Primlox to the shores of Crestwood, teaching them about friendship, responsibility, and that the greatest treasures aren't always what they seem.