Captain Kirk’s entire backstory explained

A century after the presumed death of James Kirk on the Enterprise-B, the TNG crew encounters one of the long-living El-Aurian survivors, Soran (Malcolm McDowell). This guy is obsessed with reuniting with the energy ribbon because it’s the doorway to what the El-Aurian people call the Nexus, a timeless paradise. Soran develops a weapon capable of destroying stars, thereby changing the trajectory of the ribbon so that he can re-enter it from the planet of Veridian III.

Separated from his ship, Captain Picard (Patrick Stewart) faces Soran alone. And in spite of Picard’s best efforts, Soran succeeds, and the Veridian star is destroyed, which sends the energy ribbon to Veridian III, where Soran and Picard enter the Nexus. Inside, Picard learns time doesn’t work in a linear fashion here. Because of this, he’s able to find James Kirk, who also “just” entered the Nexus, even though both their entries took place a century apart. It takes some doing as Kirk believes the Nexus will give him a second chance to live his life, but eventually, Picard convinces Kirk to exit the Nexus to help him stop Soran.

They leave the Nexus before Soran destroys the Veridian star, and Kirk distracts the El-Aurian long enough for Picard to set his rocket-launching device on self-destruct, which destroys the rocket and kills Soran. But during the conflict, Kirk is caught on a metal bridge as it’s knocked free of its moorings and falls to the ground. Picard finds Kirk pinned under the bridge, already dying. Kirk’s last words to Picard are “It was … fun.” Then, as he feels death approach, Kirk says, “Oh my,” and he embarks on his final voyage.