Book Two of Two.
When the Original "Enterprise" destroyed a Romulan Warbird, they released the Artifical Quantum Singularity fueling its warp drive into the area of space known as the Badlands, nearly destroying their own ship in the process. When the "Enterprise-D" later attempted to map the region, a reappearance of the mysterious singularity nearly killed Commander Riker.
Shortly before their fateful encounter with the USS "Voyager", Chakotay's Maquis ship encounters the singularity while returning from a supply run. Barely managing to hold the ship together, the singularity causes them to be discovered by a Cardassian warship and they flee deeper into the Badlands - where Captain Janeway, aided by the badly damaged Cardassian ship, will soon follow.
Years after their disappearance, Deep Space Nine's USS "Defiant" is sweeping the Badlands for a trace of the singularity and makes a horrifying discovery - the orbit of the singularity around the Badlands is decaying, and it will soon come in direct contact with the plasma storms and matter of the Badlands, which could prove cataclysmic for the entire Quadrant. But Gul Dukat has plans of his own!