In the reimagined Nouvelle Tokio City, once Tokyo Bay's domain, a facade of serenity masks the city's inner turmoil plagued by rampant crime. Enter Senmuji Maito, a remarkable 15-year-old: brilliant, dashing, astute, and a versatile athlete. As the head of the Senpuji Trading group and a wealthy magnate, he channels his resources into creating the 'Brave Express Squad'—an assembly of diverse robots, each endowed with unique capabilities. Leading the charge is Gaine, equipped with unparalleled artificial intelligence and a distinct persona, capable of transforming into formidable trains. Ready to spring into action at a moment's notice, these robotic heroes traverse the globe swiftly via an advanced railway network to combat any crisis that arises.