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.
Jacen and Jaina Solo are off on adventures of their own, and now it's time for their younger brother Anakin to begin his training at Luke Skywalker's Jedi Temple on Yavin IV. He befriends a girl from Tatooine named Tahiri and soon discover that they are both having the same nightmare. Believing that the Force is calling them on an adventure, they sneak out of the academy, discover an ancient Jedi Master, and are soon in way over their heads. . .
Beginning his training at his uncle Luke's Jedi academy, eleven-year-old Anakin befriends fellow student Tahiri, and both children are plagued by mysterious dreams that beckon them toward the dark side of the Force.