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 Rebel forces have found an Imperial conspiracy involving contaminated bacta, a deadly substance that can poison entire planets. In order to stop the Empire, the Rebels travel to Thyferra…where they are trapped by a squadron of stormtroopers! Your mission: to escape from Thyferra…before it's too late.