Starbase 28

It's 17 years after the return of Voyager. The Alpha quadrant has been preparing for the return of the Borg, primarily by investing massive R&D in offensive and defensive weaponry.  During the long peace, the Federation/Klingon alliance has been wearing thin, with the younger factions seeking a return to the old ways.

Meanwhile, the Federation, taking advantage of a detent with the Romulans, have cautiously begun to work to with them on holocloak technology -- a combination of a holodeck and a cloaking device.  Technically, this is a violation of the treaty of Algeron, which forbids the Federation the use of cloaking technology.  While the treaty is technically between the Federation and the Romulans, the Federation's willingness to forego cloaking is a lynchpin of the Federation/Klingon alliance.

The consensus at Starfleet is that the free races of the Alpha quadrant must work together if the next Borg invasion is to be successfully repelled. However, because the Klingons, due their racial hatred of the Romulans, are unlikely to agree with this strategy, Starfleet is keeping the holo-cloak research under wraps.  Because of his broad understanding of both the Borg and Alpha Quadrant interracial politics, Captain Picard has been given full authority over the entire project.

Meanwhile, a Borg cube visits a desert planet searching for additional biological diversity to strengthen the collective. When a Borg unit becomes infected with an viral exomorph, the infection forces a break with the collective. In order to prevent re-assimilation and to find a safe haven to propagate, the infected cube leaves Borg space.  By chance, it stumbles onto a Klingon mining freighter that belongs to the House of Mi'qoch, the Klingon clan that's responsible for the Klingon Empire's anti-Borg programme.

Jureth, the eldest son of the House of Mi'qoch, though the liaison between the Klingon Empire and the Federation on anti-Borg projects, has not yet learned of the growing cooperation between the Federation and the Romulans.  His brother, Kephren, is of one of the young rebels who despises both the Federation and his Federation-tainted brother.