Though successful, some of the Federation forces, Picard included, are left stranded when the Transwarp Portal collapses due to a destabilization of the inter-spatial transwarp manifolds. Starfleet Command then orders Picard to seize control of it and launch a counteroffensive into the heart of Borg space in the Delta Quadrant, into the Borg staging grounds.

Intrigued, Picard discovers a new type of transwarp gate called a Transwarp Portal, capable of sending fleets of starships from one quadrant to another almost instantly, thus giving reason as to how the Borg managed to get so deep into the Alpha Quadrant undetected. After routing the attempted foothold, Captain Picard discovers a new type of nebula - a tachyon nebula.

They have created a new ship capable of assimilating entire worlds in just a few seconds. PlotSet just six months after the events of Star Trek: Armada, the Borg once again threaten the Alpha Quadrant.