The city of Nouvelle Tokio stands where Tokyo Bay once did. While it appears prosperous and peaceful at first glance, the city is plagued by crime. At only 15 years old, Senmuji Maito is a remarkable boy: bright, handsome, athletic, and intelligent. He also happens to be the leader of the Senpuji Trading group and a multi-millionaire. He uses his personal fortune to create the "Brave Express Squad", a group of robots endowed with various special abilities, such as the ability to transform into trains. Their leader, Gaine, boasts super artificial intelligence as well as a distinct personality. In times of crisis, the squad can appear anywhere in the world through the advanced railway system.