When Earths natural resources run out, mankind stand divided in its efforts to survive. With every country on edge all it took was a single shot to send everybody into a panic and destroy everything in sight. But all that is depressing so instead let's focus on playing a defense game. Build up your defenses, towers, units and buildings to combat the unending wave of enemies that are coming after you. Quickly upgrade your units and buildings and arm them with new guns and weapons. With each turn you have another chance you build up your base and make it impossible from anyone to every get through.