I received this book for free from Publisher in exchange for an honest review. This does not affect my opinion of the book or the content of my review.

Princess Lira is siren royalty and the most lethal of them all. With the hearts of seventeen princes in her collection, she is revered across the sea. Until a twist of fate forces her to kill one of her own. To punish her daughter, the Sea Queen transforms Lira into the one thing they loathe most—a human. Robbed of her song, Lira has until the winter solstice to deliver Prince Elian’s heart to the Sea Queen or remain a human forever.
The ocean is the only place Prince Elian calls home, even though he is heir to the most powerful kingdom in the world. Hunting sirens is more than an unsavory hobby—it’s his calling. When he rescues a drowning woman in the ocean, she’s more than what she appears. She promises to help him find the key to destroying all of sirenkind for good—But can he trust her? And just how many deals will Elian have to barter to eliminate mankind’s greatest enemy?

To Kill a Kingdom is a loosely based Little Mermaid retelling. It follows Princess Lira one of the most dangerous sirens who one time a year, rips a prince’s heart out. Her collection keeps growing with now seventeen Prince’s that she has murdered. But when the Queen decided to punish Lira for taking a heart too soon before her Birthday, she turns her into the thing that Lira hates the most - a human.

Prince Elian loves the ocean and is the only place he calls home despite being an heir to one of the most powerful Kingdoms. He is a pirate that travels on his ship with his crew while hunting Sirens, and has given himself a name as a notorious Siren killer. When he discovers a naked woman in the middle of the ocean, he knows she is far more than what she appears - but she promises him help finding the Eye of Kato - a powerful weapon that can take down the Sea Queen.

As far as as sirens, mermaid books go, I think this is the best one I have read in a long time. The author does a good job with how she handled mermaids and sirens a like and I found it interesting and original. The writing was really good too and for the most part kept me engaged, despite some pacing issues.

That being said, I felt like this book could have made an interesting adult book. Sometimes the character roles make you forget just how old everyone is and when you finally remember, it sometimes felt hard to believe. Like Elian is about 17 to 18 years old and yet he is one of the most feared Pirates and spends his life killing sirens and building his name around it, at times his age felt off. Until, you remember that he was also completely naive when it came to Lira. He found a naked woman in the middle of the ocean, with no ships in sight, and she seems to know a lot about sirens as well as their action - and he couldn’t put that all together?

The pacing was good for the most part, I did love the world and the world building. I did wish there was a bit more, but I get how the story was supposed to flow and be fast paced. Of course, most of the story ends up being about the crew travel to a Kingdom that holds the Eye and the rest 10% or so dedicated to a battle. At that point I found that I was reading the story just to finish it.

In my honest opinion, for me the book sits at between 3.5 and 3.75 stars but because this was one of the better siren, mermaid books out there I did round it up to 4 stars it is definitely worth the read if you enjoy those type of books because thus far it is one of the better ones out there. I did enjoy it and I did find the writing really good and loved the world the author created.