Like the first book in the series, this was a fast and action-packed story about badass characters and a series of unique and magical worlds. I loved it just as much as I loved A Darker Shade of Magic, and despite a few smaller complaints I was very satisfied with this as a sequel. 
 The book got off to a strong start, Lila's storyline in particular. (The opening chapters of her boarding the pirate ship and being badass and singing her creepy little song gave me CHILLS, it was perfect and I love her sososo much.) I loved getting to see the new life and reputation she'd built for herself in the time since ADSoM, and learn more context about the other places that lay beyond Red London. Kell and Rhy's POVs back in Red London were interesting if not quite as exciting. The new character, Ojka, was intriguing, and so were the chapters about (view spoiler)[ Holland's survival and takeover of White London. (hide spoiler)] 
 To be quite honest, there wasn't really much of a consistent plot in this book. While ADSoM had one central thread tying all of the characters and their actions together (the black stone and the desire to either possess or get rid of it), A Gathering of Shadows felt somewhat...disjointed. A lot of things were happening, but the connection to an overall plot was a bit vague at times. However, as I really enjoyed getting to know the characters better and all of the action sequences, this wasn't really that big of a deal for me. 
 Something I did find problematic was the portrayal of the other empires. The people who supposedly inhabit the other two thirds of this world are diminished to only a few defining physical features: the Veskans are tall and bulky, while the Faroans are dark-skinned and have a tendency to wear jewels embedded in their skin. I was looking forward to the prospect of getting to meet people from the other empires, and get a further glimpse into the politics of Arnes, Vesk, and Faro. This seemed promising at the start of the book, particularly when Rhy and the king and Queen were discussing the royal guests, but it felt like a loose thread that disappeared and never really showed up again. The foreign characters were more scenery than actual people; as far as I can remember not one of them actually had a significant conversation with a main character. This felt like a missed opportunity to add more depth and complexity to the setting and plot. 
 On the subject of characters, Lila was once again my favorite and an absolute delight to read. She's smart and determined and always surprising, with a fierce and stubborn independence that drives her to be constantly on the move and seeking the next adventure. She's more than a bit arrogant at times, and I distinctly remember one line where she felt the need to point out her "not-like-other-girls" attitude (which did annoy me slightly), but overall these flaws are what endear her to me. Lila is a badass heroine, and she's imperfect in ways that make her seem real and sympathetic. 
 I felt a slightly stronger connection to Kell in this book as well. Thanks to the magic linking his life to Rhy's, we were able to see more of his feelings and reflections than in ADSoM. Yes, he was a bit angsty at times, BUT *puts hands of hips and speaks directly to Kell haters* he has a lot of shit to deal with, okay?? It makes sense for him to be moody sometimes, he's kinda earned it at this point. 
 Rhy got a bit more characterization in this one, too, and I'm interested to see where the story will take him in the third book. In the first book he was pretty much your likable--if a bit stereotypical--flirtatious royal, but the bond between him and Kell seems like it's starting to bring out a darker side of him. 
 Alucard was a great addition to the cast of main characters, I just wish we'd gotten POV chapters for him so that I could have learned more about his backstory and motives. I want to know more about (view spoiler)[ his relationship with Rhy and his motives for returning to London. Side note: I totally did not see the whole thing between him and Rhy coming but once it came up I was VERY on board with it. (ship puns? anyone?) It seems like they both still really care about each other, so I really want to know what made Alucard leave and Kell hate him so much??? (hide spoiler)] 
 I'm also still not sure how I feel about Kell and Lila having a romantic relationship. I can feel that they definitely care about each other a lot, but it just seems more platonic than romantic to me. Idk. I'm much more okay with it than I was during the first book, though, so I guess I'll see what happens going forward. 
 I feel like I always tend to focus more on negatives in my reviews even when I really enjoyed a book, so I just want to emphasize again that this book was a lot of fun to read!!! My complaints are pretty minor in the whole scheme of things, so I'll end this review on that note so that I can go pick up book 3! :)