Catherine Fisher left plenty of plot threads dangling at the end of sci-fantasy thriller "Incarceron." "Sapphique" picks up where the first book left off, answering countless questions and revealing more about the mysterious cyber-prison and the legendary hero Sapphique. Fisher writes beautifully, and she wraps up the story in a satisfying way. 
 In the Prison, Attia and her friend Keiro manage to con a crazy magician into giving them the Glove of Sapphique, a magical item that can connect a person's mind to Incarceron. However, Incarceron can only realize its ambitions if it has the glove, so it sends monsters, mayhem and death after the two teenagers -- even as it becomes to fall apart. 
 In the Realm, Finn is starting to doubt whether he's truly the lost Prince Giles, just in time for the queen to trot out a Pretender who looks exactly like him. Now both he and Claudia are in mortal danger, especially since Jared has become ensnared in one of the queen's malevolent plans -- which might include a civil war. 
 Somehow I get the feeling that Catherine Fisher was more comfortable writing "Sapphique" than "Incarceron" -- mainly because she gets to reveal pretty much all the secrets of Incarceron and its world. The biggest problem is that this book feels like it should have been split in half and published as two halves; the first and second halves are REALLY different from one another. 
 Once again, there's one plot set in the mechanical prison and the other in the stagnant Realm, connected but separate for most of the book. Her writing is absolutely exquisite ("They say he is making a man, out of rags and dreams and flowers and metal") and filled with starlight, silver and crumbling ruins where castles should stand. At the same time, plenty of ghastly monsters fill Incarceron, such as the ghastly multi-bodied Chain Gang. 
 And Fisher drives her characters all the way to the finish line in this book. Finn has to unravel his own past and discover if he truly is Prince Giles, even as he transforms from a confused moody boy into a charismatic young royal. And Jared -- who was mainly the Obi-Wan Kenobi of "Incarceron" -- gets to shine, a wise sage who is facing not only his own death but the death of his world. 
 In fact, Fisher brings out depths in many of the characters -- the arrogant ruined Queen, the former Warden, the spirited Attia and the completely loopy Rix. Some are limp like Caspar and the nasty little Pretender, but most are excellent. 
 "Sapphique" would have benefited from being turned into two books, but it's a truly enthralling second part to the story of Incarceron and the people trapped inside it. Lovely.