It took a fucking moon. A fucking moon! In a nutshell, a race of super warrior aliens who lived outside of the force as the Jedi know it came from another galaxy and started a war. Within a short period of time, they took over half of the galaxy with their technology made from bioengineering instead of machines. They also had some operatives who got their ahead of the main population who could disguise themselves to look like other beings. Instead of hyper-drives to go through hyper-space, they had some bio-engineered creature called a "villip" that would create wormholes, or something like that, to allow them to travel through hyper-space. One of the operatives set a trap and put one of these villips on a planet that he knew Han and Leia Solo would be at to try to kill them. The villip created a ridiculously strong gravitational pull, and pulled the moon out of orbit. As the Solos-Chewbacca ran to get on the Millennium Falcon to escape, Chewbacca stopped and grabbed Han and Leia's youngest son, Anakin, and threw him into the ship as it was pulling away, but could not get to it in time. The ship took off, the last scene is Chewbacca defiantly raising his fist as the moon crashes in to the planet. For the next 9 books of the series, Han is trying to get out of a deep depression at the loss of his best friend. It's fucking terrible. What's worse, Anakin dies several books later leading a team of young Jedi on a raid to kill the source of some beast that the aliens bred to specifically track and target Jedi. They had to kill them for their survival, as they were being killed one by one. Anakin dies saving the other Jedi, including his older sister Jaina. The series got seriously dark. Then, after all that was over and they made friends with the aliens, in the next big series Jacen becomes another Darth Vader, kills Luke's wife Mara Jade, and is ultimately killed by his twin sister, Jaina. The series is great. If you've never gotten into it, I recommend starting. There's like 50 books to read.