The novel is set three hundred years after events presented in the Mistborn trilogy. The world has moved on and technology has kicked in. But magic is still there, and it has also evolved. New type of humans with magical skills are introduced here - the Twinborn. These people can combine some skills of Allomancer with those of Ferruchemist. I thought it was an interesting twist as it wasn't too much off the beaten track and the implications of a combination like that should be familiar enough to anyone who has read the Mistborn books. Also, combining magic that relies on manipulating metals with a world going through technological revolution is a nice choice. Firearms and trains fit well into the world of Allomancers and Ferruchemists.
The plot doesn't strike as original and interesting at first. The protagonist, Waxillium "Wax" Ladrian, travels from the Roughs (a Frontier-like setting) to the capital city (Elendel - rings a bell, doesn't it?) after learning about his uncle's death. He assumes the duties of head of the house and gets involved in running business as well as finding his place among the city's nobles. Wax soon learns that life in this new place can be as dangerous and wild as in the Roughs and that he cannot really put his work as a lawman completely behind him. He is accompanied by Wayne, a young bandit-turned-lawman, who is also a twinborn with a very peculiar set of skills. I thought that Wayne was a bit too goofy and laid back to be treated seriously and I actually wished Sanderson had toned this character down a little.
"The Alloy of Law" offers some interesting insights into how progress affected the medieval-live setting of world presented in the Mistborn series. It's well structured and coherent with decently developed characters. I suppose anyone familiar with Sanderson's previous work will enjoy reading this one as well. Once again, he shows that he excels at leading the reader on, only to throw enough twists in the plot in the end to make them see everything in entirely new light. By forcing a new perspective on events that happen in the novel he also set things up for what might be a very intriguing continuation of the story.