This story is a sequel to Liberté, Égalité, Fraternité
After the battle for the Crystal Empire. Extensive searching in the lower levels of the Crystal Castle have unearthed what is possibly the largest and most comprehensive plan to destroy Equestria since Nightmare Moon's return. Now informed and armed with some magitech as well. France has dispatched The Charles de Gaulle and his battlegroup to the Guiana Passage in order to investigate the remnants of the ancient Alicorn Empire. What is revealed during the battlegroup's expedition would create the largest crisis modern Equestria needs to face with.
(Do note that you can read this story without reading the prequel, but it is recommended)