A girl's luck changes when her world changes upon itself, sending her back and forth between a world she knows and another that shouldn't even exist. Working with her parallel self from that other world, the two must adjust to their alternate form when visiting the other's world, as they search for a way to escape the chains of misfortune they are bound to.

While this story is the conclusion of the trilogy, it is also fully capable of standing alone in its own light, as the world of Celese itself is no longer a place the characters will be journeying through. However, the events of the story are a spoiler for all previous books, in case that matters to anyone. This book has an additional chapter after the final chapter that represents the trilogy conclusion, and should not be read until all three books are read first. Fortuna Verto continues the events of Essentia Animus to advance society into a sci-fi interpretation of Celese, bringing events to a distant world of another star. At the same time, events interpret a real-world advancement into a similar sci-fi age of another planet that shares Earth's galaxy, a planet that has also been linked by the Celesi Veil. English remains predominant in both worlds of the story, but the presence of both sides makes certain Aethyx terms stand out, while Earth-styled scientific terms will also stand in a powerful contrast. Instrumentation remains an important aspect of the Elemental Era, but the influence of the gift has grown distant after discovering the superiority of the elements. Harnessing the elements had eliminated some of the original limitations of instrumentation, allowing for a self-sustaining focal source that provides solutions to problems such as automation. This turns the development available from the previous modern-day sense of a fantasy to one that is deep-future. Finally, opening access to the passage across the veil will open this progress in comparison to a very similar deep-future parallel world without such fantasy elements, contrasting the laws of physics with the laws of elements in a convergence of time and space.