The Southern Sun is a seedship, or a spacefaring vessel that contains large amounts of people, whose mission is to colonize a new world. Its voyage has lasted generations, so many of its inhabitants have been born and will die without ever setting foot on solid ground. This does not please the antagonist, Elijah Kalgan, who conspires with the pirates infesting the nearby Corona Borealis system and the ship’s Chief Engineer MacPhearson. Kalgan hatches a plot to disrupt the Southern Sun’s navigation systems and use the Enforcers, the ship’s police force, to hijack the ship and direct it towards this system. At this point, the inhabitants of the Southern Sun will have no choice but to accept his “generosity”.

Kalgan sabotages a key part of the ship just as an important professor’s shuttle is on a landing trajectory. The loss of guidance control causes the ship to explode. The ship’s pilot, Dave Ryder, is able to escape, but the professor dies in the explosion. This sabotage seals off the flight deck for a number of weeks, which gives Kalgan the opportunity to attempt to wrest control. With the Enforcers in his hand, and with the flight deck out of commission, he holds the entire population of the Southern Sun hostage. Commander Jansen and Captain Devers enlist Ryder’s assistance, aided begrudgingly by Jansen’s daughter Dr. Lea Jansen, to regain control of the ship. —Wikipedia