A Feather So Black is the first book in the Fair Folk series, a romantasy proposal written by Lyra Selene, and which represents her adult debut, published by Orbit Books. When the Folk stole the High Queen's daughter, they left Fia, a rare changeling behind; magic has been lost from the kingdom, and the Folk are hated by most. By extension, Fia is also hated due to her origin.

However, the High Queen has raised her to be a spy and a weapon for the kingdom, as her own daughter; her actual daughter, Eala, is lost and bound to Tir na nÓg, cursed to only show her true form during nights. But when a hidden gate to the Folk realm is discovered, the Queen tasks Fia with retrieving her daughter and break the curse, in the company of Prince Rogan, Eala's betrothed. 

But once they start their journey through the Folk's world, their mission will prove to be harder than it seemed; not only due to Rogan's feelings towards Fia, and the mystery behind Eala's curse, but also because Fia's starts developing a bond towards the dark-fae captor to which Eala's is bound, Iaran.
And seriously, Selene has outdone herself at creating Fia; raised as a weapon, made strong by the circumstances, and she's only trying to fulfill the Queen's mission. You find yourself cheering for her and her cursed love, especially once the secret behind Iaran is revealed; she's snarky and decided, and at the end will be put in front of tough choices.

Even with the clear influences you can guess in the plot, Selene manages to include certain twists that make it really enjoyable to read. Romance wise, I found it really engaging to read, kinda slow burn but well threaded in between the plot advances, reinforcing the emotional weight implied in Fia's journey; maybe I would have liked to know more about Iaran, as it felt a bit too abrupt how Fia falls in love for him.

The magical nature of Tir na nÓg is perfectly captured through the onirical and descriptive prose of Lyra Selene; the attention to detail and how many of the Celtic mythology is blended into the world makes it even more memorable, in conjunction with many sentences that by themselves deserve to be highlighted.

A Feather so Black is an excellent debut, which blends Celtic mythology with romantasy plots and tropes; emotional damage is all over there. And after how it ends, we can only hope time passes faster so we receive A Crown so Silver as soon as possible.