The Emperor's Soul is a novella that takes place in the same world as Brandon Sanderson's debut novel, Elantris. It focuses on a master criminal named Wan ShaiLu who's found herself on death row unless she can fulfill a forbidden task appointed to her.
When Shai is caught replacing the Moon Scepter with her nearly flawless forgery, she must bargain for her life. An assassin has left the Emperor Ashravan without consciousness, a circumstance concealed only by the death of his wife. If the emperor does not emerge after his hundred-day mourning period, the rule of the Heritage Faction will be forfeit and the empire will fall into chaos.
Shai is given an impossible task: to create—to Forge—a new soul for the emperor in less than one hundred days. But her soul-Forgery is considered an abomination by her captors. She is confined to a tiny, dirty chamber, guarded by a man who hates her, spied upon by politicians, and trapped behind a door sealed in her own blood. Shai's only possible ally is the emperor's most loyal councillor, Gaotona, who struggles to understand her true talent.
Time is running out for Shai. Forging, while deducing the motivations of her captors, she needs a perfect plan to escape…
Sanderson introduces a new magic system in this story, called Forging. It has to do with the carving of "soulstamps," which can rewrite an object's history. The entire process is very hard to explain, and in the novella itself Sanderson explains it over a decent amount of time. While Forging is very hard to do successfully, if someone with the right skill works for enough time—usually over years—they can Forge something as ridiculous as a human soul.
Shai is forced to Forge the soul of the most well-known man in the entire Rose Empire in only one hundred days, which is virtually impossible. Thankfully, her captors don't know the slightest thing about Forging, so over this amount of time she can plan her escape without the others knowing what she's up to. The Emperor's Soul is about what transpires during those one hundred days.
The narrative of the book is almost entirely from the point of view of Shai, allowing the reader to get to know her and sympathize with who she is. Though the world may not approve, there's a reason she does what she does. As always, Sanderson delivers with his amazingly well-crafted world and characters. During Shai's captivity, she begins to develop a fondness of the arbiter Gaotona, some of her guards, and even the emperor himself. An emotional aspect of the story is that even if Shai truly can Forge the emperor's soul in such a short time, he won't actually be the emperor that once was. He'd just be a copy, no matter how real that copy was.
In the end, The Emperor's Soul by Brandon Sanderson is a fantastic read. For a short tale, it's very well-developed and makes the reader feel at home in the fictional world. If you can spare a few dollars, I very highly recommend it.