Yuri Otani is forced into the Alien Party at middle school, a group dedicated to capturing aliens attempting to enter the school grounds. Her kit includes a Borg, an alien-like creature that's meant to keep her safe, but Otani is terrified of the very thing she's supposed to be protecting against. She finds some comfort in her partners, Kumi Kawamura and Kasumi Tomine, who are more confident and skilled in their mission.