The colony of Esperanza — founded when the spaceship Magaleansh reached its new home planet of the three suns in 2020 — has grown into a functioning society, but space has now brought danger to its doorstep. A wormhole opened near the planet and something passed through it. Recon ships Lewis and Clark investigated and made a grim discovery: Earth has been invaded, its population enslaved, and its resources plundered by alien hordes. Esperanza could be next. In response, the United Government forms the Counter Alien Force (CAF) — an elite unit of the planet's best scientists, engineers, and soldiers — tasked with defending humanity's last free outpost before the invaders arrive.