Who, or what, is X.E.R.O.?! Unable to maintain the human guise of Aaron Stack, X-51 finds himself a fugitive from the law! And to add to the heat, fanatical federal agent Peter Gyrich and a foe of the X-Men (whose identity we¹ll keep secret for now) also want to pull the plug on our beleaguered Machine Man! And wait¹ll you see Xero, the technological terror that they intend to unleash upon him! But what strange and sinister connection links him to our beloved X-51?! We¹ll give you a hint: he harkens back to the very beginning of it all and adds disturbing depth to the Machine Man mythos!
— Description from Comic Vine community (comicvine.gamespot.com).
