Takeshi Kido and Kentaro Shiratori are friends who have spent nearly their entire lives together. One night, a strange entity emerges from a lake and attacks them. As Takeshi and Kentaro are on the verge of being defeated, a mysterious being named Kopu contacts them, revealing that they are the chosen ones destined to inherit the power to protect the world from an evil entity named Goumon. They now join forces to transform into Barom One, a being with superior abilities who fights to protect the city.