Merlin's Chosen Book 4 Children of the Chosen - Merlin's Chosen, #4

The war with the wyvern ended years ago and Chandra and Chase's twins have reached their eighteenth birthday and will receive their full powers. On the evening before their birthday, Chandra receives a new prophecy from Merlin. This new prophecy will drag not only their children into battle but Jason's son, Gavin, as well. She's also told that a guardian will be there to watch over them in the battle to come.
It seems as if their defeat is assured, the kids have minimal training and no battle experience. Will they prevail or will this put an end to the legacy of the Chosen?