Under Foot — Christopher G. Nuttall

Earth has fallen... the United States and the Middle East have been occupied by alien forces, while the rest of the world is collapsing into chaos. And yet humanity is still fighting; the underground resistance fights a bitter insurgency against the aliens, with the population forced to choose between resistance and collaboration. The fight seems hopeless, yet humanity dares not lose. If the aliens win, resistance will not only be futile, but inconceivable. Earth has fallen, but the battle is far from over.