Hostile alien mother ship is quickly approaching Earth. Mankind has been forced to seek shelter in underground bases to hide from a constant bombardment of the surface. As a leader of one of those bases, you have to develop a weapon able to destroy the alien for good while also expanding your base and dealing with enemy fighters. The game gets more and more tense as the mother ship descends at the end of each round. Will you be able to reach the end of the research track before your base suffer