Books like A Giant Problem

I don't plan to go into great detail about the storyline, because I'm a firm believer that a story can only be truly reviewed by a person's impression of the story. I think it would be a waste of time to go over the plot again...that's what the title page of the book is for. Ok, there is so much to talk about!!! The Nixies are crazy, the mermaids are way meaner than I anticipated, and basically everything is going crazy!! These poor kids!! And Nick is so freaking conflicted about everything, the kid is going to have a nervous breakdown soon I swear!They plan and they plan to get rid of the giant problem, only for everything to turn to shit the moment they do!!! I cannot even put into words my reaction when I got to the end of this book! I was borderline brain dead!!! I honestly responded with a load squealed "WHAT?!" after I turned the lats page. I have to finished this series pronto!!