In the 22nd century, Toby Tenma is a teenager who lives in the futuristic city-state of Metro City, which floats above the polluted surface on Earth. His father, Dr. Tenma, works at the Ministry of Science, alongside Dr. Elefun. They create the Peacekeeper, an advanced defensive robot fueled by using two powerful energy spheres with opposing properties, respectively in colors blue and red from a star fragment discovered by Dr. Elefun. The two scientists brief the President of Metro City, Stone,