After receiving a flyer from Maina Ichii—a member of the idol group ChamJam—and seeing her perform at a local concert, Eripiyo falls in love with Maina and decides to devote her life to supporting the shy and reserved rising star. Eripiyo's charismatic presence and iconic red tracksuit soon give her recognition as Maina's one and only unrivaled fan.

Whether it be a performance or a small fan gathering in the middle of nowhere, Eripiyo is guaranteed to be at every event Maina participates in. Not even an injury or Maina's seemingly cold attitude toward her can stop Eripiyo from pursuing her dream of seeing her beloved idol perform at the world-famous arena Budoukan.