Caged
I don't know why this is considered BDSM by some. There's abuse, yes, but it's not sexual and it's not consensual. It's abuse. I liked that this is a sequel to another story, giving me more information about the world. I read this one before the first one, not knowing it was a sequel. It was quite good and didn't really need to be read in order.
Happy ending? Yes, HEA.