Born from the strong emotions of their creators, self-contained pocket dimensions known as Phenomenon have begun forming across Japan. These false worlds overwrite the reality of an affected area and will only be undone if the maker is defeated or appeased. In response, a military-sponsored task force known as Trinary is formed, and its three members—Miyabi Koigasaki, Gabriela Lotaryńska, and Ayami Kunimasa—specialize in dispersing Phenomenon. Caught in one of these Phenomenon during her favorite idol's concert, Tsubame Ouse is saved by the timely arrival of Trinary, and together they are able to resolve the incident. After these events, Tsubame, along with newcomer Kagura Uzuki, decides to join the current Trinary team. As the girls struggle to balance their everyday lives and their responsibility to handle each new Phenomenon that appears, they realize that their own reality also has its own distinct set of problems.
