Fever is the extremely dark sequel to Wither and I felt that it was done extremely well. It followed the vein of the series perfectly but it did feel difficult to read at times because everything was just so dark and negative; it felt like nothing good was going to happen to them. 
 Through Rhine's eyes, we truly see how bleak the situation is. She feels bad for Gabriel who is not adapting well to the outside world and then she gets kidnaps by a band of prostitutes and then, Vaughn somehow finds her. It's just sad, sad, sad. 
 But there were a few positive surprises along the way, particular in the form of Maddie. I love how her story arc, as well as her mother's, overlaps with Rhine and Gabriel's and honestly, the story is just progressing so well. 
 The ending! OMG, the ending! It was so perfect and the cliffhanger is understandable but I can't believe I have to wait so much longer for the sequel. Everything pretty much went to hell in the last third of the book and honestly, I don't know how everything's going to work itself out. But OMG! OMG!!