Despite her petite stature, Iroe Genma, a senior at the local high school, is frequently called "Elder Sister." She leads the school"s Model Club, where members assemble plastic replicas of cars, boats, robots, and more. Alongside her are two juniors: the fierce Hazuki "Okappa" Okamoto and the logical Makina "Makimaki" Sakamaki. While they set out to fulfill club responsibilities, a host of diversions constantly pull them away. From internal skirmishes to tutorials on confessing feelings, the trio finds themselves embroiled in a range of zany and downright absurd adventures. Their main tasks include designing kits, painting models, and preparing presentations for the annual school exhibition. Despite their differences, they form an unlikely trio that thrives on chaos.