This was waaaay so much better than the first book! THERE ARE JUST SO MANY FEELS! 
 Okay. Okay. So, Hollow City was full of all the elements that I usually like in books that I read. It was thrilling, exciting, very unpredictable and intriguing in so many good ways. I was completely engrossed in the characters, in their world. Hollow City wrapped me from the very first page - the time stands still as I read and hours had passed. Oh, I can't help but fall in love with them in every single page. 
 Hollow City picked up where Riggs dumped us exactly where we left off from the first novel. It had two parts, btw, the only novel in the trilogy that had two parts. I won't spoil too much on what happened. I want you guys to read it. Seriously. Read it. 
 There were new characters introduced. I was a surprised that Riggs considered animals too as characters, which was really clever and witty. Who would have thought of that, right? I just love the new character, Addison! He was a peculiar dog. But hell yeah, he was so friggin' funny! He lit up the gloomy atmosphere of the children! He's very cool dog. There were more new characters but Addison was special for me. So, there you go. 
 Now, let's focus on the story line. Riggs really did a great job on this part. Hollow City really had a great concept, not just this novel though but the whole trilogy. It was so beautiful and well-written where Riggs brilliantly constructed backstories where one could really see how their backgrounds and experiences shaped their personalities and destinies. It had so many action-packed scenes, I guess every chapter had those kind of scenes where I also felt tired every end of the chapter. Most of all, it had jaw-dropping twists and turns. 
 And also, I didn't know why, but I was really looking forward to seeing the pictures because damn you Riggs, the story and the pictures perfectly matched each other! How the heck did you do that? 
 Anyway, I have to say that I am very much excited to read the last book, because that cliffhanger. That cliffhanger! 
 Maybe I am overrating it. But who cares? It deserves all the praises and great reviews. 
 Final rating: 5 SOLID STARS! 
 PS: Before reading this book, I found out that Tahereh Mafi was Rigg's spouse. Isn't that awesome? Riggs and Mafi are now the king and queen of surprises!