In the shadows of Earth, Doom Guy's victory on
  Phobos was but a dark omen. Hell was coming, and humanity was cornered. Teleportation experiments on Mars' moons had set the stage for apocalypse.
                     
As Hell's forces tore into Earth, the Global
Defense Force prepared for its deadliest fight,
sending Doom Guy and his squad to seal the breach.
Chaos erupted, plans disintegrated, and
communication faltered, leaving each marine to
face the horror alone.
                          
One warrior remained'a lone soul, battered but
unbroken, fighting against impossible odds in a
last stand for humanity.