In the forest just outside the town of Little Nova lives the local Hmong shaman, Niam Tais. Hlee Khue, a Hmong girl, brings Niam dinner every Wednesday and Friday. Hlee sets off to bring Niam the dinner her mother prepared for the important woman. On her way, Emilia, her classmate, stops her and accuses Niam of killing their friend's dog laughing at the shaman. Furious, Hlee runs past Niam's house. She sees a falling star and wishes to find where she belongs. As a young girl, Hlee's mother would tell her folktales from their ancestors, the Hmong people. As a child living in a small town in the U.S., Little Nova, Hlee told her classmate the story of the Moon Emperor. His daughter was taken and forced to marry the Serpent God who lives at the bottom of the sea. At night, the Emperor would peer down into the water, and if you ever pointed at the moon, he would send his rainbow-scaled dragon down to Earth to slash your ears. Falling stars were the Emperor's tears over his daughter. The classmate ridiculed Hlee and she stopped telling her stories. Hlee feels foolish for even wishing on a star in the first place. She finally gives a worried Niam her late dinner and heads home. The next day, Niam asks Hlee to spend time with her new guest, but when Hlee walks up and see a white teenage boy sitting outside Niam's house, she is surprised. The boy, named Argus, says his father is friends with Niam. A few days later, Hlee and Argus come across a patch of silver-dusted forest, as if a moonbeam hit that direct spot. Hlee tells Argus about the Moon Emperor; he doesn't ridicule her. Over the next few summer months, Hlee and Argus spend more and more time together, eventually becoming more than friends. Quickly though, Argus falls ill, his skin looking greyish and his eyes sunken, but Argus doesn't seem worried. One night, Argus and Hlee decide to go to the End-of-Summer Festival where they run into Emilia and her friends. Emilia begins talking to Argus, infuriating Hlee. Hlee runs away from the festival and avoids Argus for the next few days. Finally, Hlee decides to take Niam her dinner. When she arrives, Argus looks even sicker. Despite Hlee begging, he refuses to go to a hospital and Hlee once again runs out and spends the next week avoiding him. On the last Friday of the summer, Hlee spots a lunar rainbow. Seeing it as a sign, she goes to tell Argus about the rainbow. No one is home when she gets to Niam's, and instead she finds them in the glow of the lunar rainbow on the forest floor. Argus explains that he chose to fall to meet his mother, but that the Earth makes him sick. He must leave with the Emperor's rainbow dragon before it's too late. Hlee is shocked when Argus asks her to come with him, but she leaps onto the dragon beside Argus and rides towards the moon.