Yobi, The Five-Tailed Fox (2007)

"Guem-ee makes Yobi promise to keep a conversation where he shared his favorite song a secret using this. Yobi later has Jong-ee promise to keep her being a fox a secret using the same gesture."

After losing her family to fox hunters, five-tailed Yobi lives in the forest with some shipwrecked aliens, far away from the humans. When one of her alien friends gets captured by a villager, Yobi has no choice but to adventure into the human world to rescue him. At the village, Yobi meets many humans, including Geum Yee who studies at a school for maladjusted children. Interested in Geum Yee, Yobi joins the students and revels in the fun of human life, but both a fox hunter and a mysterious shadow man are on her trail.