A.D. 2067. Vár Syndrome, a disease that causes a sudden shift in its host's psyche, inciting violent behavior, is ravaging a remote corner of the galaxy. To counter it, the Tactical Sound Unit Walküre is deployed, along with Delta Flight, to suppress the Vár outbreaks. Freyja Wion leaves her melancholy life behind in an attempt to make it to the Walküre auditions being held on planet Ragna.