As she smiles at customers and makes small talk with regulars in a Hong Kong bar, Kat's every move is being watched by an older woman, a pimp who answers to the name "Mama-san."

The 23-year-old from the Philippines has been forced to sell sex for Mama-san and her organized crime network since December, when she was moved to Hong Kong under a recruiter's promise of a well-paying job and easy working conditions.

A single mother whose own mother is too sick to work, Kat jumped at the chance to earn a high salary. But soon after she arrived in Hong Kong, Mama-san confiscated her passport and sent her to work in the bar alongside other trafficked women.