Within a world broken by an ancient civil war, skilled assassins will kill anyone for a price. Known as Lady Merciless, the greatest assassin in the Five Lands, Amethyst hides a terrible secret from the Coterie of Assassins that hold her in thrall - one that could mean her death.
When she is falsely implicated in the murder of Aerba's Crown Princess and the theft of their legendary Fire Opal, Amethyst is hunted down and captured by the princess' brother, Valerian. Things only get worse when his father makes her carry the Cursed Weapons of Aerba as punishment.
Forced together, Amethyst and Valerian set out to find the Fire Opal and the assassin. But as they work towards their goals, their destinies now entwined, things spiral out of control as dark forces move against them. With the Curse hanging over Amethyst, and the Coterie after Valerian, both their lives, and their hearts, are in danger.