Incarceron by Catherine Fisher

This book has a rather unusual setting, and I gave it a rating of five out of five. Incarceron is a prison with a life of its own, literally. Finn is the main character living inside the prison, while Claudia is the main character living on the Outside. Finn believes he's from the Outside and has visions of past memories, but most people doubt that he came from somewhere else. He receives a crystal key as part of a ransom and hopes to use it to escape Incarceron. However, the band of thieves ruling inside the prison, the warden and queen living on the Outside, and Incarceron will not let that happen. Meanwhile, Claudia's father oversees Incarceron, although they live on the Outside. He's not a kind man and has arranged for Claudia to marry the son of the queen. Claudia was originally supposed to marry the queen's stepson, but he died unexpectedly. Claudia suspects murder, but she has no evidence. She finds a crystal in her father's study and discovers she can see and communicate with Finn. Little do they know how closely their past and futures are joined.

I had some trouble early on as I tried to grasp the meaning behind the setting of Incarceron. It's location should surprise you! The conflict and plot became clearer as Finn made plans to escape, and Claudia's wedding day drew nearer. I liked how the author kept me wondering about what was really going on even as Finn made his way through the prison. There always seemed to be lingering, unanswered questions. The questions are answered as the plot nears the climax, and a sequel seems likely with the way things were left during the resolution. The themes of friendship and trust are strongly demonstrated.