Sapphique picks up about two months after Incarceron ended. Finn has escaped the Incarceron, but as he escaped the warden of the prison enters bring with him the two keys, the only way to enter the Incarceron. With Finn the only one to escape, this left his oathbrother Keiro and Attia in the Incarceron which he promised he would find a way for them to escape as well.
Not only does Finn want to find a way to rescue his friends but he must deal with his own problems in the realm. The realm isn't exactly what he thought it would be. Constricted by the protocol, the realm seems sometimes worse than the prison to Finn. The Queen will do anything to discredit him. And then, another boy announces he is Prince Giles, and Finn finds himself doubting his true identity and Claudia also begins to doubt him. And with no memories of the past, when he use to be Giles, almost everyone else doubts him as well.
In the prison Attia and Keiro try to find a way to escape on their own. Keiro lost faith in his oath brother and is determined to find a way outside. Attia meets up with magician named Rix who is in possession of Saqqhique's glove. Which might be another way to escape the prison and Attia will do anything to possess the glove herself.
Attia and Keiro go through more wings of the prison. Each wing is unique and interesting to read about. The Incarceron itself leads Attia and Keiro through its vastness as they try to find the way to the prisons heart.
There is tons of adventure in the book. It is a quick read with twist and turns. It leaves you hanging with Attia and Keiro and then switches over to Claudia and Finn or visa versa. So, you are always wanting to read more to figure out what is happening to the other characters. The ending is good doesn't leaving you hanging. But, in my opinion, there could be another book.