The following contains spoilers for Star Wars: Shadow of the Sith, now on sale.
One of the most interesting aspects of the Star Wars Sequel Trilogy was the bond between Luke Skywalker and Rey. Using Leia's help, she tracked down the exiled Jedi Master on the oceanic planet of Ahch-To after he had disconnected from the Force when Ben Solo became Kylo Ren. Despite his reluctance, Rey was adamant she could convince him to join her and fix the galaxy in The Last Jedi.
Unfortunately, while Luke did help out, he ended up dying, which left fans with a bitter taste in their mouths. Some were angry Luke didn't get more screen time, training Rey in the light side of the Force and reuniting with the rebels. But while it seems like Luke and Rey only really connected in this one film, Star Wars: Shadow of the Sith revealed he found her way before.
In the Star Wars novel by Adam Christopher, Lando Calrissian found clues suggesting a smuggling ring was running rampant. He was looking for his missing 10-year-old daughter, Kadara, and locked onto Ochi of Bestoon. He learned Ochi was targeting a family, not realizing this was Rey and her parents -- with Palpatine eager to pay off the bounty for his kin before The Force Awakens. Lando recruited an eager Luke, who had had visions of a Sith resurgence. This worried him, as he was restarting his temple after he thought the Sith had died with Palpatine. It led to them tracking the family down, trying to get to them on a gas-mining colony called Nightside in the Therazar system.
Sadly, things went awry when the sinister Zargo took them prisoner rather than helping to smuggle a six-year-old Rey, her mom, Miramir, and her dad, Dathan, to safety. Zargo was trying to betray Ochi, which led to a civil war. R2-D2 ended up hacking into the main computer as the family fled, giving the bot's crew visuals but no audio. Little did Luke know he was staring at his future apprentice and another Star Wars Chosen One destined to bring balance to the Force.
As the firefight broke out, Lando laid down sniper cover to kill off Ochi's men and other soldiers wanting to capture the family for their own gain. Meanwhile, Luke had to scamper off to investigate the Sith presence he felt -- Kiza and the viceroy possessing her, Exim Panshard. This culminated in Lando contacting the family via radio. He eventually helped them escape in a ship, the Goldstone, before he reunited with Luke after Panshard went back to his lair.
Luke was in two minds, wanting to go save the girl because he sensed a unique spark in her but also wanting to hunt the Sith Lord down. Unfortunately, they wouldn't be able to track the family again, with Ochi eventually finding and killing the parents after Rey was hidden on Jakku. However, the die was cast, and ultimately, this tragic skirmish put Rey on the path to finding Luke years later to begin her training in the Star Wars Sequel Trilogy.