Star Wars Callista Trilogy

The Star Wars Callista Trilogy is a series of novels set in the Star Wars universe. The trilogy includes the books Children of the Jedi, Darksaber, and Planet of Twilight.
Children of the Jedi takes place several years after the events of Return of the Jedi and follows Jedi Knight Luke Skywalker and his new companion, Callista, as they investigate a mysterious distress call from a lost Jedi outpost.
Darksaber takes place shortly after the events of Children of the Jedi and follows the adventures of Luke Skywalker, Princess Leia, and Han Solo as they try to stop a group of criminals from using a powerful weapon called the Darksaber to destroy the New Republic.
Planet of Twilight takes place after the events of Darksaber and follows the Jedi Knight, Luke Skywalker, and his companions as they investigate a strange and deadly disease that has appeared on a remote planet and discover a sinister plot that threatens the entire galaxy. Along the way, they encounter an old enemy who has returned with a vengeance.