So after the previous book of this series was such a blast to read, I hoped that this book, the series finale, would be just as memorable. Unfortunately, while not bad, it also wasn't great.
On the good side of things, we finally get some very welcome information about Dr. Catalyst and I'm glad the series didn't make his identity too obvious. He's in top bad guy form here, certainly makes for a memorable villain and the segments from his point of view in all four books are always so engaging and stand out. His newest creation, the Swamp Cat, while not as creepy as the Blood Jackets, is a cool and threatening menace all its own and a welcome addition to the critter menagerie in this series, especially when it came to the attacks, which were savage, brutal and no-nonsense, and I really appreciated that. Another positive was Calvin's character development was nicely done in this one.
Unfortunately, in terms of the story itself, this one's just kinda average. Dr. Catalyst wants to kill Emmet, and that's about it. The thing is that, while it's understandable that Dr. Catalyst hates Emmet and sees him as what turned the tables and made every one of his plans go sour, when you read the series as a whole, it's honestly been more a team effort between both Emmet and Calvin, in which Calvin is more often the more effective one at foiling the villain, and it doesn't help that Emmet, while he has his moments to shine, is generally just an annoying whiny brat whose constant quips and jokes fell flat and were entirely unfunny, and I just never warmed up to him. It generally felt to me that Emmet was miscast as the main character, especially compared to the more level-headed and competent Calvin.
Overall, there's not much to the plot, so outside of the Swamp Cat attacks and a couple of good chases, a lot of the segments can get dull, it made me want things to be a bit more dynamic and varied. There's also how the cast has been minimized a bit in this one too, and it's especially noticeable when you take into account that Raeburn and Riley had a big role in the last book, but in this one, the both of them and Stuke don't appear at all and are merely just mentioned, so their lack of presence was a big flaw for me. Then comes the final act of the book, the climax, and while it starts exciting, it ends very abruptly. Not just the final confrontation feels rushed, but so does the ending of the book. It ends as though a TV show episode would end and you'd wait for the next episode next week. It's really sudden and jarring, it doesn't feel like a proper conclusion, just falls short of being exiting or satisfying.
Overall, while this wasn't a bad book, it wasn't particularly good either. It was just okay, but "just okay" feels disappointing considering it's the series finale, and especially because it came after the excellent third book. In general, this series was a mixed bag, but I'm still glad I read it.