Based on the manga by Hitoshi Tomizawa, ALIEN NINE follows the exploits of a precocious sixth grader named Yuri. Attending a school plagued by frequent alien attacks, Yuri is given the unenviable job of eliminating the extraterrestrials from the school. Forced to wear a gross symbiotic alien helmet in order to do the job, Yuri bravely puts on her game face for the good of the school.