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 battle against the evil Empire rages on as heroic men, women, and aliens of the Rebel Alliance continue their struggle to end the era of darkness. But now a mysterious visitor comes to the Rebel fortress located atop Mount Yoda, bringing ominous news. Kadann, Supreme Prophet of the Dark Side, plots to capture and destroy the carbonized body of Trioculus and take control of the Empire. Meanwhile, the Rebel Alliance races to save the archaeologists of the dying planet Duro, only to discover an incredible mystery in the underground tunnels, a secret that depends on a perilous… Mission from Mount Yoda.