The Outrim Void is a dangerous place, rife with the remnants of ancient civilisations, pirate havens and ravenous aliens waiting to surge across borders into unclaimed territory. Its only hope for survival is the narrow stream of stars known as the Sindalian Main. If the secure flow of trade can be restored there, the region might one day rise above its blighted circumstances.

The Travellers are sent deep into the Void when they are assigned to the remote Imperial Navy base at Dpres. There they must take command of a joint-force task group and proceed along the Sindalian Main to Tktk. Their mission is to interdict the planet to protect its native sophont species, the tktks.

They soon discover that the Outrim Void is far different from Imperial space. Once you leave home port you enter a wild frontier. On the way to Tktk the Travellers must handle a plethora of problems including assisting colonists, protecting Imperial corporate interests, navigating the complex politics of the region, and possibly staving off an alien invasion. In addition, they must somehow manage to keep the task group fuelled and supplied without the ready assistance of the Imperium. Their objectives quickly expand and threaten to derail the primary mission. Fire on the Sindalian Main puts the Travellers to the test. The glory and honour of the Imperial Navy is at stake!