Background: Alternate universe where the Borg successfully invaded Earth. Prior to this event there were already divergent events between this universe and ours. Doctor Crusher remained at Starfleet Medical and O'Brien married Keiko prior to the invasion. Chief Argyle also remained on the Enterprise. Elizabeth Shelby was brought aboard as the Borg expert. After Picard was captured by the Borg, Riker was promoted to Captain. An attempt was made to rescue Picard using a strategy that involved separating the ship and going in via shuttle (with Worf and Data aboard), but Riker felt that using the Antimatter spread suggested by Commander Shelby would be too risky. The rescue attempt failed as the Borg concentrated first on the shuttle. They were only able to rescue Worf before the shuttle was destroyed. The saucer section itself too massive damage in the ensuing battle and Doctor Pulaski, Counselor Troi and Keiko O'Brien were among the casualties. The Borg proceeded unimpeded to Earth where they systematically began assimilating the population. It was a slow process that would go on for the next 2 ½ years, the Enterprise stardrive section making a nuisance of itself but never really slowing down the process.
In 2369 their sensors picked up a ship near Mardion Three, a dead world. It was another Galaxy-class starship, another Enterprise from a parallel universe. Riker decided to have the entire bridge crew of that ship beamed to the cargo bay. After a fight, the other crew stood down when they recognized their counterparts. Captain Riker explained to Captain Picard the situation and that it wasn’t long until Earth itself was dismantled and destroyed. Riker wanted them to help him snatch Locutus, as they had done once before on their side. It took convincing but Picard eventually agreed to help them - they had days before the rift that sent them there collapsed. They would use a variation of the same plan, with Picard’s Enterprise (now under Commander Shelby’s control) would fire the antimatter spread while Riker’s Enterprise would draw their fire, allowing Picard and Data to use a shuttle to penetrate the Borg shields and beam aboard the cube. The plan went without a hitch, aside from the fact that Locutus was no longer aboard the cube. Both Enterprises withdrew from Earth. Long-range scans revealed Locutus was likely in the Starfleet Command Complex in San Francisco. Picard’s Enterprise once again engaged the cube while Riker’s ship approached from a different angle and beamed down an away team consisting of Picard, Riker, Data, and both Worfs. They successfully retrieved Locutus, but the native Worf was killed. The Cube lost all interest in Picard’s ship and went after Riker’s vessel. Shelby gave up on trying to damage the cube and veered off back towards Earth. Riker’s Enterprise took a heavy beating while they tried to find a way to access the Borg central net, its command structure varied on the one from the other universe. They lost all their shuttles in a last-ditch attempt to score damage on the cube and then cutting beams began tearing into the hull. The other Enterprise, now under O'Brien’s command, returned and briefly took the pressure off, but then both ships were snared. Picard was able to tap into the Picard trapped inside Locutus, and the “Eat” command was sent to the Borg. The Cube shut down as all Borg attempted to feed at the same time, overtaxing the cube and effectively killing it. Repair teams from both ships patched up Riker’s Enterprise and Picard found out from his freed counterpart that he’d been the one who created the rifts and they were closing faster than they thought. The other Enterprise, capable of faster speeds than Riker’s ship, soon left the other one in the dust, but had to stop when Riker found that his O'Brien had attempted to switch places with theirs. His O'Brien returned without a fight, and the other Enterprise sped away back to the rift and their own universe.
Appeared in Star Trek: TNG #47-50, DC-V2. There’s some continuity issue as Riker lists Guinan as one of the casualties early on but later when her name is brought up he has no idea who she is.