Fiery Waters

Eren and Armin always had a dream as children. They wanted to break free of the wretched walls, and explore the world. They wanted to find the wonders of the worlds, Water, Deserts, Mountains, and all other beauties taken from their hands by the Titans. They fought, killing Titan after Titan, and even discovering that Eren has the capability of transfusing into a Titan, and offered a chance for human survival. Soon, after having their small wold all for him, they turned against his branch in the Survey Corps, being abandoned from the walls, and wanted by the Military Police.
Soon after this even unfolds, the walls take a serious turn. The horrid Colossal Titan returns, to destroy the walls again. And soon, humanity finds themselves defenseless against the Titans. And no sooner than the next wall down, all the walls have been demolished. And with no protection, Eren, Armin, and Mikasa, are left on their own to survive. Will they make it? Can they defeat their foe? Or will they fail?