Ultimo and Vice were created in feudal Japan to be "perfect good" and "perfect evil" as Dr. Dunstan's "last curse upon this world." A thousand years later, a monster wearing a Noh mask wreaks havoc in Farmless City of West Tokyo, while the S.K.A.T. Police unit cannot stop it. Ultimo plunges in to destroy the monster, explaining that the creature is about to show its true form, Vice, Ultimo's evil counterpart. The mechanical boys end their fight both badly damaged, and the movement of select groups around Japan begins.

(Source: Wikipedia)