Saya Mihashira attends Kumashite High School in Tokyo during 2034. She co-hosts the daily lunchtime school radio show "All Day Nippon" with her identical twin, Sayu Mihashira. On air, Saya frequently vents frustration over the prolonged delays plaguing the school's east wing construction and openly rails against the principal. The program features listener mail segments focused on everyday frustrations and includes a corner dedicated to imagined statements from specific individuals, often showcasing wordplay submissions from a listener using the pseudonym "Mayuri." Saya's impulsive, outspoken commentary during broadcasts contrasts with her sister Sayu's efforts to moderate her remarks. The twins deliver their show using distinctive cat-themed microphones and wear cat-eared accessories, highlighting their shared fondness for feline motifs. Beyond radio, Saya and Sayu serve as enthusiastic play-by-play commentators for the school's baseball games, providing energetic narration of athletic events like Yuzuki Tsugayama's baseball performances. Saya possesses yellow/blonde hair and red eyes.