The Borg return -- with a vengeance! Blitzkreig attacks by the single-minded aliens with their hive mentality and their mission to assimilate every intelligent being they encounter are leaving whole worlds aflame. No one knows how they are slipping past Starfleet's defences, so Captain Jean-Luc Picard and the Enterprise crew are detailed to find out -- and to put a stop to it if they can. Meanwhile, thousands of light years away, Captain Will Riker and the crew of the Titan follow bizarre energy pulses to a mysterious, hidden world.

There they find a figure out of legend: a Starfleet captain long thought dead. And at the same time, over in the Gamma Quadrant, newly promoted Captain Dax and her crew investigate the wreck of the Earth starship Columbia NX-02, missing in action for more than two centuries.