what else is slaved?
Diamonds.
Sex - there's a sex slave trade, apparently. What kind of freak looks a person in the eye as they abuse them?
some clothing is slaved.
So, you can wear sweatshop suits with diamond cuff links while chugging sweetened mocha while somebody's son or daughter pleasures you. While you pet a puppy mill puppy with one hand while soaking your feet in a bucket of fried caged chicken.
[...and it was then that the ship was boarded by pirates]
In chapter 4, the slaves revolt, but no one tells them when it's supposed to happen.