In the sprawling urban landscape of Nouvelle Tokio City, constructed atop the former Tokyo Bay, an illusion of wealth and tranquility conceals rampant criminal activity. Senpuuji Maito, a fifteen-year-old prodigy acclaimed for his intellect, appearance, and athletic skill, stands apart. Beyond these personal achievements, Maito heads the Senpuuji Trading Group and possesses immense wealth. Using his vast resources, he establishes the Brave Express Squad, a team of robots each equipped with unique powers. Their leader, Gaine, features advanced artificial intelligence and a distinct character. These robots can transform into trains and navigate a sophisticated worldwide railway network, allowing them to swiftly address emergencies across the globe.