As mankind extended their reach into space they eventually discovered a large alien technological device on the surface of a newly colonized planet. After sending a scientific and expeditionary force to research the device it was inadvertently activated and shortly thereafter the Draelus invasion began. The device turned out to be a Portal that linked to the Draelus' home system - they were just waiting for someone to "knock."The Draelus quickly shot out in all directions from the planet and the military in turn had to spread its forces thin in an attempt to slow the Draelus advance on multiple fronts. A full assault on the planet containing the Portal was deemed too risky as the military would need to remove other lines of defense in order to mobilize a large enough strike force. Subsequently an experimental fighter called the Scythe was constructed - a hybrid of human and captured Draelus technology.