A Cage of Gold and Lies

In this modern day, urban fantasy retelling of Rumpelstiltskin, can a young woman escape a cage of gold and lies? Growing up on the streets, Zari used to dream of a fairytale ending. Until she found out that magic was real, and witnessed the horrible consequences. On that day she learned that the billionaire who lords over the city keeps people with the gift of magic as his personal slaves. And none can escape him alive. When Zari's drunken father boasts that "his daughter" has magic, Zari will do anything to protect her little sister.
Even take her place as a slave. But how long can she survive the billionaire's cruel tests and tasks when she can't cast a single spell?