Lakota has returned to Deep Space 17 after a month-long mission. The crew is looking forward to a brief moment of peace, however, this tranquility is short-lived as DS17’s sensors detect an anomaly at the edge of the dangerous Ryton system. Fleet Captain Nazir, who is aboard DS17 discussing recent starship disappearances, learns that the USS Proteus, an Echelon class light cruiser, has detected a subspace phenomenon. The analysis indicates a large vessel inside the aperture, closing in on Federation space.

Captain Callen Varro quickly orders Lakota and the USS Proxima, a Sovereign class exploratory cruiser, to investigate. Upon arrival, they find a subspace aperture and unite with Proteus in time for a damaged Borg sphere to emerge. The sudden appearance of the Borg sphere triggers traumatic memories among the crew. Nazir takes command of the unit, ordering immediate defensive measures as the Borg sphere begins to regenerate, with the ominous voice of the Borg Queen echoing through their communication systems.

The Lakota, Proteus, and Proxima engage the Borg sphere in an attempt to prevent it from fully regenerating. However, their initial efforts prove ineffective. Faced with a difficult decision, Captain Nazir decides to lead a risky infiltration mission to gather intelligence and potentially disable the sphere from within. Away teams from all three ships are sent into the Borg sphere. Inside, they find extensive damage and drones in stasis, making retreat impossible.

The away teams discover that the Borg sphere is part of a larger fleet that infiltrated the quadrant months ago, only it never reached its destination. They devise a plan to disable the sphere’s regeneration matrix while Lakota and the other ships provide cover. As the team moves deeper into the sphere, they encounter resistance, leading to intense combat and the clever use of Starfleet technology to overcome the Borg.

Just as the Borg sphere begins to fully regenerate, the away team is ambushed and nearly captured. They manage to disable the regeneration matrix, but the sphere activates a self-destruct sequence as a last-ditch effort. Realizing that the self-destruct could create a subspace rift capable of destroying the entire sector, Keziah must choose between evacuating immediately or attempting to stop the sequence. Despite their efforts, the team fails to stop the sequence in time and must make a desperate escape as the sphere begins to collapse.

The collapse of the sphere creates a subspace rift, threatening to engulf the Proxima, which is suffering from engine trouble. In a heroic effort, Proteus and Lakota use their deflectors to close the rift, saving Proxima from destruction.

Back at DS17, Nazir receives troubling news: the USS Hypatia has gone missing in a nearby sector. Task Force Commander Captain Callen Varro reactivates Lakota squadron, now including Proteus and Proxima, and dispatches them on a new mission to locate Hypatia, setting the stage for their next adventure.