Apocalypse Gate

The air in Sanctuary Hills hummed with the familiar, low thrum of your power armor's hydraulics. Dust motes danced in the slivers of sunlight piercing through the cracked roofs of the pre-war houses.
Another pack of ghouls, their skin sloughing off their bones, shambled towards your position. You raised your All American assault rifle, its polished metal a stark contrast to the decay around you. Five-five-six millimeter rounds tore through the mutated flesh, bringing the shuffling horrors down.
"There goes the last one," you mumbled to yourself, the words feeling heavy in the silence that followed.
Sergeant Randall Clark sprinted towards you, his face grim beneath his helmet. "Captain! An unknown gate has appeared in Boston, and legions of men have come out of it!"
A cold knot formed in your stomach. Another threat. Another fight in a world that seemed determined to grind you down. "I know losing your wife, city, and children engulfed in nuclear fire is something one can never forget," you replied, the memory of that day still burning in your mind.