After being sent to this world by an E.V.O named Breech, Rex finds himself in Equestria as an Earth pony stallion. Along with trying to figure out what the heck happened to him, he also has to defend the ponies who live in this world from a person named Van Clise, and the E.V.O's that are being sent here to kill Rex. It's a good thing he can still use his Nanites, or he would be destroyed by everything this world has to offer.