A Court of Wings and Ruin - Sarah J. Maas

Feyre returns to the Spring Court, determined to uncover the plans of Tamlin and the powerful, sinister King of Hybern, who threatens to destroy Prythian. However, to achieve this, she must play a deadly game. One wrong move could destroy not only Feyre but her entire world. The battle with Hybern is in full swing, and forces of good must ally with dark forces if they want to defeat the greatest evil together. Feyre must decide whom to trust and seek allies in the most unexpected places. Yet, it seems traitors are everywhere, and Feyre will often have to resort to magic and fall into traps. Soon, two armies will clash in a bloody, uneven battle for power...