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 Youtini Expanded Universe Ranking system is a 1-5 scale that ranks EU book quality, difficulty, and importance. Books closer to Level 1 are easier to read and understand, more important, and of higher quality.
The Rebel Alliance have captured a damaged new model of Imperial warbot on Xeron and decide to ask the assistance of the droid populated space station known as Kligson's Moon in repairing the droid so the Alliance technicians can study it. Kligson agrees to repair the droid, but R2-D2 and C-3PO must accompany the warbot to observe the operation since Kligson intends to keep the droid after it's repaired. However, another droid on Kligson's moon has other ideas as the former Imperial droid Z-X3 plans to use parts of the warbot to repair his own war droid and lead a revolt against Kligson. But Kligson had anticipated this and sent a decoy to lure Z-X3 and his followers out into the open when he would launch his own warbot against them. With the battle over, R2-D2 and C-3PO record the schematics of the warbot and return to the Rebels, while Kligson moves his station from its current orbit to a more secret location where the Empire cannot find it.