Waverly and Kieran are finally reunited on the Empyrean. Kieran has led the boys safely up to this point, and now that the girls are back, their mission seems slightly less impossible: to chase down the New Horizon, and save their parents from the enemy ship. But nothing is truly as it seems…Kieran’s leadership methods have raised Seth’s hackles— and Waverly’s suspicions. Is this really her fiancé? The handsome, loving boy she was torn from just a short time before? More and more, she finds her thoughts aligned with Seth’s. But if Seth is Kieran’s Enemy No. 1, what does that make her? 

In one night, a strange explosion rocks the Empyrean—shooting them off course and delaying their pursuit of the New Horizon—and Seth is mysteriously released from the brig. Seth is the most obvious suspect for the explosion, and Waverly the most obvious suspect for releasing him. As the tension reaches a boiling point, will Seth be able to find the true culprit before Kieran locks them both away—or worse? Will Waverly follow her heart, even if it puts lives at risk? With the balance of power precarious and the clock ticking, every decision counts… every step brings them closer to a new beginning, or a sudden end...

Review:
After loving Glow as much as I did, I went into this book with fairly high expectations. I know that sequels are often not as good as their predecessors, but I still hoped for the best. Though these expectations were not quite met, though  I did quite enjoy the book, wishing only that I had read it earlier.

This is a classic example of a cover switch midway through a series, though in this case, I think it was for the better. The old covers were nice, but the new ones suit the series much better, in my opinion. The new covers feature a much more futuristic look, even incorporating the windows from the spaceship into the design. It features a much lighter design than the original cover for Glow, making it stand out among the legions of dark YA covers. I really loved the hints of stars you could see throughout the cover, they brought it together nicely while giving it a si-fi look.

The characters in this series are very dynamic. They were in a constant state of change, though not all for the better. It was nice to see characters reacting accurately to the state of trauma on the ship, because in reality not everyone would rise to the occasion. Kieran was one of those people who didn't quite rise to the occasion, he started to become Waverly's worst nightmare. I loved how Kieran didn't end up becoming the idealistic boyfriend character, but a much more dark and undecided character just trying to make the best of the situation. Waverly was a great character, she was making the right decisions and trying to gain influence on the ship without staging a full on revolution. Seth was by far my favorite boy in the book, even though there wasn't a huge relationship between him and Waverly, but they definitely have great chemistry. The story was narrated by Kieran, Seth and Waverly. Seth and Waverly were my favorite points of view, Kieran's was a little bit on the political side, where Seth and Waverly were often nearer to the drama.

The story was the only element of the book that was lacking. It just seemed to get very slow at points, and it didn't cover all that much ground in the trilogy when it came down to it. It wan't bad or anything, but it just wasn't even up to the standards of the first book. The ending was a good one, it left off with a bit of a cliffhanger, leaving me dying for the final book once and for all. The writing was just as good, it featured the amazingly descriptive writing that the author brought forth in Glow, but the story just seemed to barely carry on. Nothing seemed to be of major importance in the grand scheme of things, just focusing on setting the plot up for a great finale.

The end makes me want the final book all the more. But, until then, I give Spark a 4/5 for falling under the notorious stereotype of sequels. I'd recommend it to fans of the first book or si-fi fans, or anyone who enjoyed the Across the Universe books.