Hen Wen first appears when Taran brings food out to her prepared by Dallben, then when Taran gives her a bath, she begins to act scared of something. Dallben then has Taran bring her inside where he uses her powers of seeing the future to reveal that the Horned King is searching for the legendary Black Cauldron and when he sees that he knows about hen wen's power he odrers Taran to take Hen Wen to a hidden cottage where she would be safe.
On their way there, Hen Wen accidentally slips away and gets captured by the Horned King's two Gwythaints that tale her to his castle. Taran breaks in and sees her in chains and being forced by the Horned King's minion Creeper to reveal the loaction of the cauldron. Taran reunites with her and the Horned Kings demands that he make her reveal the cauldron's location, but Taran refuses as he promised Dallben he wouldn't reveal it to anyone. The Horned King states that the pig is now of no use to him and orders her to be be-headed, Taran reluctantly agrees and begins to reveal Hen Wen's powers.