The Rhino is the new Version of the Rex. After finding a depot of the new-gen stealth nuclear missiles, and the blueprint of the Rail Cannon, a little group of north european terrorists (a unit that calls itself "Sturm und Drang") kidnapped a whole bunch of engineers in order to create a new Metal gear, capable to carry an heavy Rail Cannon, but with all the new technologies used in the construction of the Gekko Mass Production Model. So, the new prototype was created. It is said that this group is ready to show the firepower of the Rhino with a massive attack (with empty nuclear shells of missiles) on the other side of the world. This said, we must point out that the target is still unknown.