Iron Kissed gets into one of the most interesting parts of the Mercy Thompson universe: the Fae. They may have come out to the public a few decades ago, but only the least of the Fae. When a small pile of the greater Fae are brutally murdered, Mercy gets involved.
We get to learn a fair bit more about the Fae in general and Uncle Mike and Zee in particular, which is nice. They’re fascinating and just alien enough to be believable. On top of that, Mercy finally manages to choose between Sam and Adam, although if it will stick, who can say… We start getting into a bit more of the romance aspects that some readers of the series are expecting–and then the final section of the book happens (see spoiler section below).
Overall, it’s a powerful book with some lovely worldbuilding and interesting characters. The romance / love triangle aspects of the book are a bit wearying at times, but they’re still a relatively minor part of the story. If that’s your thing, power to you. If it’s not, it’s easily skippable.
-- SPOILERS –There is a rape in the final section of the book. On one hand, it's a very powerful scene and from what I've read from other reviewers, it seems to deal relatively realistically with the consequences. Despite (perhaps even worsened by) the fact that Mercy can shrug off magic no one else should be able to do and kill someone she truly loves, she was still violated. It's an interesting direction to take the story; one that writers have to be extremely careful to use. Someone being raped, be it the protagonist or a minor character, is often overused as 'character building' or motivation to drive the plot forward when there are often other less stereotypical / potentially problematic ways to do the same thing. On the other hand, perhaps a well written scene can help people understand / heal.