Julie, seven years old, moves with her family to Texas. Julie's classmates treat her differently and she's lonely. One day, crying in her room after school, Julie hears a tap on the window. She opens it and in flies a unicorn named Sparkles. Sparkles asks Julie to keep a secret friendship because no human is supposed to talk or see a unicorn. Sparkles gives Julie a whistle bracelet so that Julie can contact Sparkles by blowing it three times. Julie and her family travel to their old neighborhood for Julie's best friend Karen's birthday party. Karen finds out about Julie's bracelet and Julie explains that it's a secret. Will Karen be angry? Sparkles brings Julie to her fairy land, showing her how unicorns get along with each other. The prince finds out that Sparkles had disobeyed the rules and has to decide whether to banish Sparkles from the fairy land.