Three boys—Kotaro, a ninja in training, Rikiya, a training baseball player and Yosuke, a studying scholar—were living normal lives in Aozora Village. One day, Kotaro, along with his father Tobe, accidentally broke the seal that links the Underworld from the Human World. Eldran, the warrior of light, appeared in front of Kotaro, Rikiya and Yosuke along with three strange machines. They were appointed to save the world from destruction as the Ganba Team and use the robot Ganbaruger.