As the leader of a group of young robusts delinquents, Kaneda spent his nights tearing through the urban wastes, racing his motorbike against rival groups. One night, while riding with his gang, his friend Tetsuo suddenly encounters a strange boy - the product of human experimentation - and is injured in the ensuing crash. Shortly thereafter, a military squadron appears on the scene to take the boy and Tetsuo away to an army research lab. Determined to free Tetsuo from captivity, Kaneda sneaks into the lab. However, a regimen of extreme experimental procedures has awakened a new power in his friend, and he is now consumed by madness...