Fever was mainly about freedom. What would we do to be free? What does it mean to be free? We follow Rhine and Gabriel after they escaped from her Vaughn, Linden and imprisonment only to be chained by so many other things in the real world. Rhine has changed a lot, but she often thinks about how her life would be if she remained in the mansion every time things get unbearable. She is determined to find her brother even though it seems impossible in the world without cellphones or the Internet. I'm actually not sure if there are such things but there weren't any phones so I'm gonna think that technology isn't in use anymore. However there is a lot of drug use, prostitution, kidnapping and even a rape attempt.
There are some new characters, prostitute Lilac and her malformed daughter Maggie, the cruel madame and a kind lady( forgot her name,sorry) whose daughter was kidnapped and who's trying to make up for the lost time with trowing herself into taking care of abandoned orphans. We get to see Vaughn towards the end and get to witness his terrible experiments on girls.
If you enjoyed reading Wither, I'm sure you'll like Fever too. It wasn't as good as Wither but it still got me to read at least hundred pages on a really busy day when I would rather sleep than read.