Have you heard about teenage abolitionist Zach Hunter who is stirring up students and adults to do what they can to free people who are ensalved around the world? He has written, Be the Change, and his publisher, Zondervan, has an info webpage with samples and news links.
I’m not big on teenage ‘activists’ but if people want to get an idea on modern slavery I recommend they read one of the books by Harry Wu. He was a slave for many years under Mao. (At one point he was much envied by fellow slaves when (after getting married) he was allowed to live in a cave.)