Sentinel (The Fifth Covenant Novel)

As the mortal world slowly slips into chaos, Alexandria Andros must overcome a devastating defeat that has left her shaken and in doubt that the war against the gods will ever come to an end. There are many obstacles standing between Alex and her happily-ever-after with Aiden St. Delphi, and now Alex and Aiden face their greatest challenge yet: they must trust a deadly foe as they travel deep into the Underworld to release one of the most dangerous gods of all time. In the shattering, action-packed climax to the series, Alex must make a terrible choice: the destruction of everything and everyone she holds dear... or the end of her own life.