Uprising by Alex Wheeler
Since X-7's defiance, Soresh has been planing two betrayals. First, he will kill Luke, then his master, Darth Vader. But when he captures Luke, his plan changes. He will use Luke to replace X-7 and have him kill his friends and Vader.
During his captivity, Luke is tortured endlessly to be forced into submission. He is sure he can defeat Soresh, but will he be strong enough?
**Book 6 in Rebel Force**
Previous book: Trapped