BBY/ABY is used to position items along the Star Wars Timeline. BBY refers to Before the Battle of Yavin. ABY refers to After the Battle of Yavin. The Battle of Yavin in Episode IV: A New Hope occured in 0 BBY/ABY.
Explore Darth Vader's early history! Picking up directly where Star Wars: Episode III - Revenge of the Sith ends, follow Vader as he receives his legendary red lightsaber and witness Vader's rise to power as a Dark Lord of the Sith! When Anakin Skywalker fell, both to the pull of the dark side and the blade of Obi-Wan Kenobi, he rose back up, more machine than man. Having lost everything that was once dear to him, he now takes his first steps into a darker world...beginning by hunting down and eradicating the galaxy's remaining Jedi! But Jocasta Nu, librarian of the Jedi Temple, is making a desperate effort to gather and preserve whatever she can of the religion's legacy. Palpatine views her as a particular threat to the Empire - does her knowledge make her a one-woman Jedi Order?