The Forbidden (Andrews)

Emmie Wilcox was only six when her sister, Roxy, was thrown out of their New York City apartment. Their stern father's military style left no room for rebellion, and Roxy was continually defiant and rebellious. Emmie is obedient, respectful. Two sisters, total opposites - yet Emmie is secretly obsessed with the mystery and imposed silence surrounding Roxy: What had she finally done to deserve being cast out of her home? Sometimes she fantasizes that she is more like Roxy than she appears. She wants excitement, and being a good girl all the time is harder than it seems. Finally learning that Roxy is a highly paid escort to wealthy and powerful men, Emmie goes behind her father's back to track down and spy on the sister she can't help but be fascinated with.