The Dark Realm. The Edgewater Chronicles, #3

A year on the run with everything to lose. The bad dream of the past fourteen months has morphed into a full-blown nightmare for Nikola and Lizzy. In a dizzying sprint halfway across the world, they prepare to face a vastly more dangerous foe-a triple threat not born of this world, and intent upon their utter defeat. Sailing into the Bay of Kotor under the cover of night, they find themselves attacked by ancient magic before even setting foot on the rocky shore.
The old country seethes with unexpected malice, and the path to their goal grows more difficult by the hour. Nikola and Lizzy search for new allies to even the odds against the malevolent forces that await under the black mountain, but can they be trusted? The lives of Lizzy's family hang in the balance as the last clash against the Ancient Ones unfolds. Can Nikola and Lizzy unlock the puzzle of their destiny before it's too late?