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. She wants excitement, and being a good girl all the time is harder than it seems. Finally, Emmie goes behind her father's back to track down and spy on the sister she can't help but be fascinated with.

Kicked out of her house because her father can no longer tolerate her constant delinquency, Roxy wanders the streets of New York, living in a fleabag hotel. Spotted by an "agent" for Madam Brittany, a sophisticated woman who runs an escort service, Roxy is taken into the Madam's "training program" where she is educated and set up with her own boutique apartment.