On a desert world a village struggles to survive. Pell's passion is deciphering the odd bits and pieces that the Ancients left behind. Her neighbors consider it a waste of time and would rather melt the artifacts down for the metal they so desperately need. Everything changes when a stranger, the first Pell has ever met, asks her to help repair Ancient machines in what the villagers thought was an impenetrable Tower. Driven by curiosity to see inside the Tower, and Moseus' promise of payment in the form of scrap metal, she agrees. In the Tower she finds three Ancient machines, all larger and far more complex than anything she has seen before. She also meets the other inhabitant of the Tower, Heartwood, and she wants to decipher his mercurial moods as much as she wants to know what the machines actually do. Almost immediately she begins to have visions, or maybe memories, of the Tower and its inhabitants, which draw her ever deeper into the mysteries of the Ancients, a tale of warring gods, and the history of the village of Emgarden.

You might be tempted to imagine this is a post-apocalyptic Earth, but no, it is not. Like every small detail in this book, the creation myths are very relevant to the secret that underlies the strange village of Emgarden and the Tower. Pell's role in her community is a digger, and she spends her time digging furrows between crops or graves for the aging population. With her spare time, she spends it trying to figure out how the various scraps of Ancient technology worked, and there are a few she has actually figured out and fixed, like a clock and a water pump. Her curiosity means she can't resist going inside the tower, and in there she finds a large machine on each of the first three floors. Unfortunately, Moseus tells her the devices will create an opening in the impenetrable wall that cuts Emgarden off from the rest of the world and that their people live on the other side and they need to return. Other than that he can tell her nothing of how they work and there are puzzling elements in each machine that Pell must solve before she can fix the next one. Then there are the visions which slowly grow more complex and seem to be showing Pell a series of events that might be in the future, but feel like memories. Since she has never been in the tower before it should be impossible, but she keeps running into small details that would confirm her feeling. By the time she realizes the truth it will be too late.

In a vague way this story reminds me of the Pandora myth. It also shares some themes with Sanderson's Mistborn with its mists and the idea of Ruin manipulating events. Sorry, no allomancy. Curiosity compels Pell to go to the Tower and while it slowly opens her eyes to the secrets of her world her work may also doom the entire Universe. This certainly isn't the first book to work this scenario but it's very well done and while not related to Earth at all, the world building is like something out of Norse mythology. The secrets are laid down in careful layers that peel away one by one until Pell understands all that has happened. Seemingly minor details are, in hindsight, careful clues. Sometimes an engineer can really fowl things up but they are also great problem solvers and this world has a terrible problem.