Aelin Galathynius has vowed to save her people ― but at a tremendous cost. Locked within an iron coffin by the Queen of the Fae, Aelin must draw upon her fiery will as she endures months of torture. The knowledge that yielding to Maeve will doom those she loves keeps her from breaking, but her resolve is unraveling with each passing day…
With Aelin captured, friends and allies are scattered to different fates. Some bonds will grow even deeper, while others will be severed forever. As destinies weave together at last, all must fight if Erilea is to have any hope of salvation.
Years in the making, Sarah J. Maas's New York Times bestselling Throne of Glass series draws to an explosive conclusion as Aelin fights to save herself―and the promise of a better world.

Celaena Sardothien has survived deadly contests and shattering heartbreak—but at an unspeakable cost. Now she must travel to a new land to confront her darkest truth... a truth about her heritage that could change her life—and her future—forever.
Meanwhile, brutal and monstrous forces are gathering on the horizon, intent on enslaving her world. To defeat them, Celaena must find the strength to not only fight her inner demons but to battle the evil that is about to be unleashed.
The king's assassin takes on an even greater destiny and burns brighter than ever before in this follow-up to the New York Times bestselling Crown of Midnight.

An alternate cover edition can be found here.
After serving out a year of hard labor in the salt mines of Endovier for her crimes, 18-year-old assassin Celaena Sardothien is dragged before the Crown Prince. Prince Dorian offers her her freedom on one condition: she must act as his champion in a competition to find a new royal assassin.
Her opponents are men-thieves and assassins and warriors from across the empire, each sponsored by a member of the king's council. If she beats her opponents in a series of eliminations, she'll serve the kingdom for four years and then be granted her freedom. Celaena finds her training sessions with the captain of the guard, Westfall, challenging and exhilirating. But she's bored stiff by court life. Things get a little more interesting when the prince starts to show interest in her... but it's the gruff Captain Westfall who seems to understand her best.
Then one of the other contestants turns up dead... quickly followed by another. Can Celaena figure out who the killer is before she becomes a victim? As the young assassin investigates, her search leads her to discover a greater destiny than she could possibly have imagined.