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.
BEHIND ENEMY LINES! HAN SOLO and his fellow cadets risk their lives to save one of their own. But not all of them will be coming back from this mission…and even if Han survives, will the Empire throw him in the brig or worse?