Eripiyo is initially a woman leading a normal life until it is turned upside down after watching a performance of the minor idol group ChamJam, which leads her to becoming obsessed with one of its members, Maina Ichii. Despite Eripiyo's enthusiasm towards her, Maina is consistently the least popular member of the group, leaving Eripiyo to take it upon herself to buy a lot of Maina's merchandise, which mainly involves singles. Due to her using almost all of her money to buy this merchandise, Eripiyo has only a single tracksuit she wears all the time. She frequently goes to ChamJam's concerts with her friends and fellow ChamJam fans: Kumasa, whose favorite is Reo Igarashi, and Motoi, who prefers Sorane Matsuyama. Eripiyo continues to work several part-time jobs to support Maina, and Maina herself increasingly becomes concerned that Eripiyo is pushing herself too hard for her.