The year is A.C.-218
It has little over 20 years since the Mariemaia Army attempted to conquer the earth only to be defeated by a few brave men and women. In the years since, there has been a maintained peace between The E.S.U.N. and the Space Colonies, with massive dis-armament and dismantling of weapons taking place on both sides. The Terra-forming project on Mars has been a slow but successful process with several inhabitable cities doting the planet's surface thanks to the resources being mined from beneath the red deserts and trading with outlying colonies. Mobile suits are viewed as a weapon of an age best forgotten and subsequently submitted for dismantling and recycling of their components as part of a treaty signed between the E.S.U.N. and the Colonies.
"It's been more than 20 years since one of these titans have been seen on a battlefield...but that doesn't mean there aren't a few lying around."