Imprisoned in a land without magic and ruled by a tyrant king, the infamous assassin Celaena Sardothien is summoned to the glass castle—not to kill, but to fight for her freedom. She must outlast twenty-three of the realm's most lethal killers, thieves, and warriors in a deadly competition. Victory means liberation; defeat means a return to captivity.

The Crown Prince provokes her, sparking a fire she thought long extinguished. The Captain of the Guard becomes her unexpected protector. But lurking within the castle's glittering walls is a sinister force bent on destruction. Competitors begin to perish one by one under mysterious circumstances.

Celaena's quest for freedom turns into a fight for survival. An ancient evil is awakening, threatening to consume her world. With danger closing in, she must unearth the darkness before it claims them all.

Will Celaena defeat the shadows that threaten to shroud her world in darkness?