With the development of a new electromagnetic induced train system, the old subway has lost it's credibility, becoming a seedy haven for prostitution and drug-dealings called "Paradise Loop". Recently, a string of murders have broke out in this area. The victims, all prostitutes, are found with their abdomens slashed open by some sharp instrument in the same manner. Why does the murderer only chose prostitutes? Can this hideous crime be committed by a human being? Or is a Boomer responsible for the killings? Soon, the investigation leads to a woman who seemingly has no connection to the crime whatsoever...

AD Police officer Billy Fonward, 28, male, was critically wounded in a battle with a defective Boomer on the run. However, he was subjected to an experimental cybernetics operation which miraculously brought him back to life. With the exception of his brain and some of his internal organs, his body parts were completely replaced with mechanical substitutes, which transmit senses in the form of electrical information, thus leaving him with only his tongue to "feel" like a human being. The use of optional weapons and protectors enables him to work with highly dangerous cases without being affected by pain, consequently keeping him calm and decisive under any situation. After returning to work, Billy is promoted two ranks to become an AD Police Special Weapons Team Commander. He is, in effect, the first experimental subject to become an anti-Boomer Cyborg Police Officer. But Billy couldn't be a hero...