n the year 2404, Earth is celebrating Voyager's 10th anniversary of its 23 year journey home. However, an elderly Admiral Kathryn Janeway acquires a chrono deflector from a Klingon named Korath and uses it on her shuttle to travel back to 2378 in the Delta Quadrant. She pulls rank on Voyager to emit an anti-tachyon pulse, collapsing the temporal distortion to prevent the Klingons from following her through.
On board her old starship, the Admiral tells her younger self to return to a nebula filled with Borg that they passed by a few days ago. She provides advanced technologies that would give Voyager the opportunity to get past the massive Borg defenses and enter a transwarp corridor. The Borg, despite spying on the ship and preparing for its attack, are unable to penetrate Voyager's new ablative hull armour nor capture it with tractor beams while Voyager destroys two Borg Cubes with transphasic torpedoes. They then come upon a Borg transwarp hub at the center, which could save the ship sixteen more years of being stranded in the Delta Quadrant.
However, the admiralâs efforts are hindered by the desire of her younger self to use the future technology to destroy the transwarp network instead of using it to return home. Trying to blast it from the inside is impossible, as the network adapts to any attack due to the control of the Borg Queen (Alice Krige, reprising the role for the first time since Star Trek: First Contact). It can only be destroyed from their end for the Alpha Quadrant contains only exit apertures. The two Janeways argue over the issue until the elder Janeway tells her younger self that Seven of Nine and Chakotay, along with 22 other crewmembers, will die if they do not take the road home, and that Tuvok will become senile from a neurological condition that could have been treated in the alpha quadrant if they'd made it back soon enough. Deeply troubled by the knowledge that she is effectively ordering her crew to their deaths, Captain Janeway discusses the issue with them, but they too decide that destroying the Borgâs transwarp hub is more important than returning to Earth, as without it, the Borg's ability to travel across the galaxy will be severely hampered and countless lives will be saved. On seeing the crewâs selfless reaction to the plan, the older Janeway rediscovers a piece of her old fighting spirit and with Captain Janeway, comes up with a plan to both destroy the hub and possibly get Voyager home.