Quick recap
Eighteen-year-old Celaena Sardothien, Adarlan's most notorious assassin, has spent a year as a slave in the salt mines of Endovier. Prince Dorian offers her a deal: win a competition among thieves and killers, become the King's Champion, and earn her freedom after a few years of service. Trained by Captain Chaol Westfall, she watches the competitors die one by one, attacked by some creature. The ghost of Queen Elena asks her to face an evil hidden in the castle. Celaena befriends Princess Nehemia and finds out that Cain uses Wyrdmarks to summon the monster. In the final duel, poisoned by Kaltain, she still beats Cain and becomes the King's Champion.

