Sequels are hard to review - they're a bit hit-or-miss and these days more and more suffer from second book syndrome: they act like a filler book to tide you over until the real action begins again in the concluding book.I'm very happy to say that Through the Ever Night doesn't have any of these problems. Authors take note: this is how you write a sequel! The book is an all-round hit - just as riveting and action-filled as the first book, and it sets readers up for what is bound to be a thrilling climax in the final book of the series, Into the Still Blue.My one complaint about Under the Never Sky was that the cataclysmic event that forced people into the Pods, and left others to eke out a living in the harsh environment outside, was never explained. This is quickly and efficiently taken care of in Through the Ever Night, with the author briefly recounting the massive solar flare that wreaked havoc on Earth's atmosphere and now causes the brutal magnetic storms that plague our characters. I wonder why this was never mentioned in the first book, it seems the solar flare should have naturally come up whenever Aria was thinking about how her life inside the Pods differed from that of the 'Savages' outside.Perry and Aria are breathtakingly realistic characters, and they continue to pull at the heart-strings in this book. The secondary cast, including Roar, Reef, Molly and Bear, add dimension and warmth to the story, and I love that Rossi handled the loyalty of the Six and the mistrust of the rest of the tribe so well. I couldn't really blame any of the characters for feeling what they did, but it frustrated me that they didn't trust Perry as their leader. On the other hand, their blind hatred of Aria disappointed me, and it doesn't seem like this issue is going away any time soon.I also liked the tension Rossi created between Perry, Live, Aria and Roar. It was predictable, and a little cruel, but I think anyone in Perry's position would have been susceptible to doubt, and I hope it all gets worked out in the next book.Finally meeting Liv, Perry's sister, was one of my favourite things about Through the Ever Night. I felt like I should know her already, after all the stories Perry and Roar tell of her, but she's even more impressive in person. I think it would have been very easy for the author to ask readers to hate Liv because of the decisions she made, but her situation is impossible and my heart was breaking for her.Through the Ever Night is a captivating sequel: populated with amazing characters and full of twists and turns that will keep you reading way past your bedtime! Veronica Rossi has quickly become one of my favourite YA authors, and I encourage readers to pick up this brilliant series.A copy of this book was provided by the publisher for review.You can read more of my reviews at Speculating on SpecFic.