Haru Nabatame, Rio Seibu, and Kyouka Tamaki's idol unit, TiNgS, is on the verge of disbandment. However, if they can fill all two thousand seats in their upcoming anniversary concert, their idol careers will live to see another day. This quota is seemingly impossible for a group like them, especially when the most people they have had at a show is 37. Fortunately, they are placed under a new talented manager—Naoki Hinase.

While initially reluctant due to past experiences, Naoki takes charge of TiNgS after sensing Haru's genuine passion for idols with his own remarkable ability to see the shine of someone who is lying. Despite the challenges she faces in this ambitious endeavor, Haru wants everyone in the world to love idols, even willing to become the shining guidepost—shine post—to accomplish her dream.