The Young Knight and His Metal Steed

A seemingly simple protection job alerts the existence of a shadowy conspiracy.
The year is 2030. The world is divided into supernational unions yet they don't control all nation-states, inviting an acceptable quantity of wars for mercenaries to find. This was the result of an alien ship crashing into the Democratic Republic of Afghanistan in the year 1985 with the supernational unions born from a world war from 1989 to 1991 that saw the use of nuclear weapons.
The mercenary group Iron Dutchman Services, after another pay cut due to the damage wrought from their last job, takes up a job offer from the Foreign Intelligence Service of the New United Nations to go to Japan to secretly protect Maria Hoshikawa, a teenage corporate heiress. One member, Tarou Ganji, seventeen years old, uses this job as an opportunity to figure out his past as Maria has a similar upbringing (growing up in a country with different physical features from its inhabitants). The risk comes in acting like a normal teenager; something Tarou never learned to do as he learned how to use a gun at the age of ten.
However, shadowy forces intend on using Maria for their own ends. They employ a man that made Tarou what he is today to kidnap her, having him work with the OVR foreign intelligence agency of the Eurasian Tsardom. This will complicate Tarou's mission as many now have an interest with a teenage girl, putting the fate of the world at risk.