City of Glass by Cassandra Clare

To save her mother's life, Clary must travel to the City of Glass, the ancestral home of the Shadowhunters -- never mind that enter-ing the city without permission is against the Law, and breaking the Law could mean death. To make things worse, she learns that Jace does not want her there, and Simon has been thrown in prison by the Shadowhunters, who are deeply suspicious of a vampire who can withstand sunlight.

As Clary uncovers more about her family's past, she finds an ally in mysterious Shadow-hunter Sebastian. With Valentine mustering the full force of his power to destroy all Shadow-hunters forever, their only chance to defeat him is to fight alongside their eternal enemies. But can Downworlders and Shadowhunters put aside their hatred to work together? While Jace realizes exactly how much he's willing to risk for Clary, can she harness her newfound powers to help save the Glass City -- whatever the cost?

Love is a mortal sin and the secrets of the past prove deadly as Clary and Jace face down Valentine in the final installment of the New York Times bestselling trilogy The Mortal Instruments.

WOW. Just wow, wow, wow! What a perfectly thrilling conclusion to an amazing trilogy. I had been waiting a long time for this one, with many unanswered questions and high expectations about how it all would end. I was not in the least bit disappointed. In fact, this book took my greatest hopes for a satisfying conclusion and exceeded them by far.

The characters that us readers have known and loved in the first two installments continue to grow and I felt so much for them while reading this book. So much was going on at all times but I never felt overwhelmed. Rather, I felt as if I was part of the exciting and crushing adventure that Clary and her friends were on. I cheered for them, I was on the edge of my seat, and my heart broke into a thousand pieces when tragedy struck our beloved characters. I believe I even shed a tear or two.

Fans of the series should feel satisfied at the trilogy's conclusion. Anyone who hasn't picked up Cassandra Clare's work yet should do so ASAP.