Oriko Fujidou, daughter of the powerful Fujidou conglomerate—the world’s leading force in vending machine development and distribution—was gifted an entire city by her father at the age of four. Over the past ten years, she has devoted herself to its growth and prosperity. However, the city's peaceful days come to an abrupt end when an enormous, unidentified invader attacks. In a desperate attempt to fight back, her loyal butler, Dr. Sebastian, gives Oriko a newly developed energy drink. The moment she drinks it, her body grows to a towering size, surpassing even skyscrapers. Though struggling at first, she ultimately manages to repel the invader. But the attacks don't stop. Each time a new threat emerges, Oriko transforms into a giant once more, standing to protect the city she has nurtured with her own hands.