From the adventure's back cover:
Two weeks to save a world...
Since you crash-landed here, Volturnus has been a planet of constant surprise and peril. You defeated the Star Devil's pirates and made contact with for intelligent races native to the planet. Your adventures with them made clear that these aliens would be valuable members of the UPF -- if they manage to survive.
The vicious Sathar are on their way to Volturnus with a fleet powerful enough to destroy all life on the planet. the Survival of the is in your hands. You must organize the defenses of Volturnus. You must unite the races of Vulturnus and lead them in a battle against the Sathar. The outcome: victory, or death for an entire world!
Starspawn Of Volturnus is the conclusion of the Volturnus series of modules for the Star Frontiers game. It can be also played as a separate adventure. Starspawn Of Volturnus contains maps and referee's notes, including information on new creatures and intelligent races.The module also contains "The Great Game of the Ul-Mor," an encounter that came be used as a re-playable game.