FoE: G.U.A.R.D.I.A.N. follows Angel and her surviving squadron of elite soldiers from The Great War find themselves in a new, destroyed land. The Pegasi above had taken it upon themselves to drop snow down on the city of Germaney below to keep the toxins down, and away from their safe cloud cities above. With the toxic snow left covering everything they once knew, the only way to survive is to scavenge anything that they can find to survive. The deadliest killer is not the lack of food or clean water here; however, instead it is the poison air that requires a gas mask to even consider breathing outside.