Hayato Hayasugi is among the select children assigned to control the Shinkalion – a clever twist on the phrase "too fast" – in order to safeguard Japan from an unknown danger. These robots are modeled after the beloved shinkansen trains and are equipped to metamorphose into formidable battle apparatus. The Shinkalion team faces the daunting challenge of defeating a sinister foe resembling a dark bullet train, and to do so, they must unite with the experienced adults of the Shinkansen Ultra Evolution Institute.