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.
The epically creative and groundbreaking Dark Empire saga concludes with a two-issue miniseries from legendary writer Tom Veitch (though this time without Cam Kennedy's trademark watercolor art). The reborn Emperor Palpatine launches his ultimate plan to transfer his essence into the form of Leia Organa Solo's unborn son! Not to mention another powerful superweapon. . .
Emperor Palpatine has a new weapon—one that can annihilate a planet. But he's not targeting a planet—he's targeting the future of the Jedi, Leia's children. It looks like a hopeless situation for Luke Skywalker, who has the critical task of protecting the children. But it's not the first time Luke has found hope where none existed. The finale to the Dark Empire trilogy is collected here.