The year when her father, a mountaineer, died on Mt. Everest, Ujuu met an alien on the mountain behind her neighborhood and became an alien fan. Because of this, when she said that she met an alien before, she ended up being bullied. She decided to carefully hide her interest in aliens and pretending to be normal became her life motto. At a strange location, she happened to find a flyer for a club named Alien Tracker. In that club, Mun Heemun, the most popular guy in school, joins as a new member but gives off a strange feeling.