Cerberus. Operation Stargate, #6

There are not many planets populated by humans at the rim of the Galaxy. Cerberus is one of those planets. It is the fourth of eight planets in the Spinner System. The Spinner System is located near the edge of Human Space. It is far away from the regular trade routes that are frequented by humans and other races, but it is still close enough for merchant ships and freighters to visit. There is not much beyond the Spinner System, except for a few rogue suns.
Cerberus is home to seven million humans and three million Sartans. For centuries, humans and Sartans lived in peace. There was no need for either race to have an army. That all changed with the appearance of a ruthless invader from the other side of the star-gate. Without an army, the humans and Sartans are defenseless against this brutal alien race. The Solar Union is sending Major Ethan Wolf of the ISS and Captain Gorini of the Anorian Special Investigation Service to Cerberus to evaluate the situation and find out what exactly is going on. They discover that the peaceful existence of humans and Sartans is just an illusion.
Freeland is run by gangs and the Sartans are exploited by a powerful company from Hyperion. The Union has no choice but to send in the military to deal with the invaders and the Cartel.