Kubota Makoto, a young gang leader, takes in Tokitou Minoru, a boy with a mysterious past. Minoru has been exposed to the drug W.A. which has transformed his right arm into a monstrous limb. The two investigate the origins of the drug that is devastating the city's underground.

Source: ANN

AniDB | ANN | MAL | Wiki (en)

Alternative setting: Shiritsu Araiso Koutougakkou Seitokai Shikkoubu