One day, like any other, the rookie guildmaster Miori Celesta wakes up without remembering anyone she knows. Despite having amnesia, she still remembers her past; The only thing she cannot think of are the people she has ever met in her life. Without having much time to talk with the people she apparently knew, Mio gets herself into some kind of war, in which battles she will meet both new people and people who knew her before she lost her memories. With these allies, the young guildmaster will try and discover the meaning behind her amnesia and its connection with the war.