The Bitterbynde is a fantasy trilogy by Australian writer Cecilia Dart-Thornton. It comprises The Ill-Made Mute, The Lady of the Sorrows, and The Battle of Evernight. In the first book of the trilogy, the story is about a mute with no memory, eventually named Imrhien, whose face is deformed due to a poisonous plant. The mute is trying to find a cure against the poisoning, a name and lost memory. The mute later meets the warrior Thorn who captures her heart. A 'Bitterbynde' refers to an unbreakable promise or oath.