Set just six months after the events of
Star Trek: Armada, the Borg once again threaten the Alpha Quadrant. They have created a new ship capable of assimilating entire worlds in just a few seconds. After routing the attempted foothold, Captain
Picard discovers a new type of nebula: a
tachyon nebula. 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, explaining how the Borg managed to get so deep into the Alpha Quadrant undetected.
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. 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. Meanwhile, the Cardassians use the sudden absence of Federation forces to begin their own offensive. The Cardassians proceed to destroy the Federation's reserve fleet. Klingon Chancellor
Martok discovers that Gul Kentar, leader of the Cardassian uprising, is in league with the Romulans. Kentar is developing a "Quantum Singularity Ship" that allows the Cardassians to summon Species 8472 ships at will. Martok leads an attempt to thwart Kentar's grab for power and destroy the project. The Klingons stop the Cardassian rebellion and occupy their homeworld, Cardassia Prime. In the final battle, Martok tracks down and kills Gul Kentar, taking out the Quantum Singularity Project along the way. The
Borg Queen, stranded in the Alpha Quadrant by the same twist of fate that trapped Picard on her side of the galaxy, discovers that Species 8472 has found a way into the Alpha Quadrant. She attempts to mass an armada to suppress this threat by assimilating native species planets, ships and technologies, but its growth is stunted by the constant attacks from the Federation. She then realizes that only by working with the Federation they can defeat Species 8472. The Federation and the Borg Collective create an alliance and venture into Species 8472's fluidic space to destroy their staging grounds by destroying the Rift Maker, thus ending the threat to the Alpha Quadrant by closing all the rifts. ==Reception==