Fortress of the Demon by Scott Tomasheski

Imagine that you can travel through time, and that you can meet your great-Grandparents and your great-Grandchildren, because THEY can travel through time, too … MEET THE ATHERTON FAMILY. Ambassador Bartolomea Atherton – a.k.a. ‘Mrs. A’ – along with her great-nephew August, and their family members and other associates on the Council of Time Defense, have a huge responsibility: they have vowed to defend the Timeline against those who attempt to change it, in their quests for wealth, power, and revenge. And when the notorious Baron Hookfinger uses his terrifying Aerofortress to reverse the outcome of the Eighth Crusade, putting the fate of Western Europe and the entire free world in jeopardy, August and Mrs. A must attempt to stop him. But first, they must unravel a centuries-old mystery… confront the supernatural forces that haunt a Transylvanian castle… and defeat the mightiest army ever assembled on Earth…