|Battle of the Hayre Expanse|
|Federation Alliance||T'Uerell's Borg Collective|
| Captain Jean-Luc Picard|
Admiral Kathryn Janeway
|1 Sovereign-class||1 Suurok-class|
|Casualties and losses|
|Indeterminate||All of T'Uerell's Collective|
Following the Third Battle of Deep Space 9, in which T'Uerell's Borg Collective was forced to retreat from Deep Space 9 in the Bajoran system by an allied fleet of Starfleet, Klingon and Romulan vessels were led by Captain Picard, proceeding on a pursuit course at maximum warp. While the Klingons believed this to be a sign of victory, Picard was more cautious, observing that without the support of Deep Space 9, the allies lost the advantage of choosing the time and place of our engagement. However, he noted that the alternative of letting T'Uerell escape so she could replenish her Borg drones and ships would be foolhardy. As such, the allies had no choice but to pursue her to whatever ground she chose for the final confrontation. Ultimately, the allies intercepted T'Uerell in the Hayre Expanse, joining with reinforcements led by Admiral Janeway.
Spotting T'Uerell's ship, the Seleya, Picard quickly realised why she had chosen the sector for her stand as sensors indicated that her area had a high concentration of polaric ion energy, which Janeway noted was unstable enough to destroy the Seleya and everything else within 100,000 kilometers. However, T'Uerell appeared to have harnessed the power of the nebula effectively. Meanwhile, the Klingons registered a large energy pocket forming around the Seleya, serving as a shield. Picard noted that he had never seen that kind of shield configuration before, noting that it had similarities with regenerative shielding encountered in the past but much more complex. Janeway determined that T'Uerell was using the nebula's unique properties to bolster her shield matrix, giving her a vast source of power to defend herself, more than any of the allies' weaponry could penetrate. As such, Janeway and Picard concurred that T'Uerell would remain at her current position indefinitely, observing that the safest place in the galaxy for her was within the string.
The allied fleets then detected an anomaly, possibly a subspace rift, from which a tachyon pulse was emanating. Janeway observed that the anomaly was a transport conduit, reasoning that T'Uerell intended to summon reinforcements. Finding that the conduit did not read the same as the ones she had encountered in the past, with a much greater energy signature, Janeway suggested that T'Uerell was sustaining the conduit from the power she was drawing from the string. Anticipating that torpedos would not be able to collapse that conduit completely, Janeway determined that the Seleya itself would have to be neutralized. (ST video game: Legacy)
As the Enterprise's chief engineer was worked on the problem, Borg ships began to emerge from the conduit, some of them failing to recognise as active on ship's sensors with highly unstable power matrix readings. Observing that the conduit was having undesirable side effects on the affected vessels, Picard suggested that all ships stay clear of them, as he predicted that they were likely to self-destruct. Receiving communications from subspace that more help was on the way, the allied fleet engaged the active Borg vessels while avoiding the unstable ones.
Soon after, the battle saw the arrival of a Borg tactical cube, with Picard knowing that Janeway had encountered one before. Acknowledging that the previous tactical cube was destroyed only after being damaged internally and with the assistance of a Borg sphere, Janeway noted that they were extremely well-armored and heavily destructive. Commander Praetus of the IRW Si'rak suggested that the allies would be better able to penetrate the vessel's armor by co-ordinating their attacks on it. Ultimately, the tactical cube was destroyed.
Meanwhile, the Enterprise's engineers formulated a plan to deal with the Seleya, with Picard contacting the Nebula-class USS Scott, which had been modified to serve as a deep space repair and re-arm vessel. Shortly after, the Scott arrived and provided four sensor pods, remaining in the system to guard the sensor pods and provide any assistance to ships that required it. Starfleet modified the Scott's sensor pods by a remote link to emit a magneton pulse, a method previously used by the Dominion. Having experimented with ways to adapt the magneton field to block certain types of subspace ruptures at their point of creation, becoming an anti-subspace weapon. Via tractor beam, each of the pods were dragged to a optimal deployment position at the opposite ends of T'Uerell's string. As the first pod was deployed and began power-up procedures, the Borg turned their attention towards the pods, which were protected by the allied vessel. Once the second was in place, the start-up sequence was finalized and the pods' pulse generators were brought online. Within 20 seconds, the magneton pulse was activated, and so T'Uerell lost the necessary power to maintain the conduit and her shields.
Losing her defense, T'Uerell ordered all Borg units to form a perimeter around her vessel. Unfortunately for T'Uerell, she had neglected to factor in that the string had a destabilizing effect on warp fields; as a result, the Seleya was limited to impulse speeds. In an attempt to cover her escape, T'Uerell brought the dormant Borg vessels out of regeneration, their activity increasing. Ultimately, however, T'Uerell was killed as both the Seleya and the remaining Borg vessels were destroyed by the allied forces, who promptly departed the nebula. (ST video game: Legacy)
During her final moments, T'Uerell attempted to contact Captain Picard but whether it was the Borg or Vulcan persona within her was unknown. A search was conducted by Starfleet of the remains of her ship but failed to detect the lone Vinculum of T'Uerell's ship that remained and powered up. (ST video game: Legacy)