Amidst the gunfights and bloodshed in a city of sin, there lived two legendary figures, known only as Bullet and Brain. Bullet, as the name suggests, is the sharpest shooter the city has ever seen and can take someone out with a pistol in less than a tenth of a second. Brain, on the other hand, is a calculated genius with excellent problem-solving skills, not to mention some cool gadgetry. These two men are called into action again when an old score involving a little girl needs to be settled.