Exodus

Earth is dying.
The damage done to Earth's biosphere by the supernova is extensive and ongoing. Humanity's only chance of surviving is to deepen their tenuous alliance with the alien race, also fleeing the supernova's devastation.
Repair the alien ship and build a duplicate for human evacuation. It should be easy enough.
But not every human is agreed on the best course of action. Someone would rather take control of the ships for their own purposes, and if Jackson and King can't figure out who it is and stop them, humanity's odds of surviving slip from slim to none.