Star Wars Legends: The Truce at Bakura
The novel takes place the day after Return of the Jedi. The Rebels are reorganizing when they get a distress call from a remote imperial outpost about a new enemy that could threaten the galaxy. Luke Skywalker is given a task force to command and goes to assess the situation. He brings along the main cast from the movies and together they discover that the alien threat is stealing human lifeforce in order to power their technology.
The only real character development that happens is Luke getting slightly better at force healing through practice and Leia coming to terms with Vader being her father.
In the end, the alien menace is destroyed, the planet that was threatened joins the Rebel Alliance, and some imperials defect.
Don't waste your time on this novel unless you're a Star Wars completionist like me. For most people it wouldn't be worth it. There are much better novels and series later in Star Wars Legends that definitely are worth reading.
Again, I'm glad I found an abridged audiobook version of this novel. I didn't have to re-read the entire thing. It was a time saver.
This is the last novel in the Rebellion era. After this we start to get into the New Republic era and the novels get better.