The Castle of Llyr

Blurb

The Castle of Llyr is a high fantasy novel by Lloyd Alexander, the third of five volumes in The Chronicles of Prydain. The story continues the adventures of Taran "Assistant Pig-Keeper", primarily on the Isle of Mona west of Prydain, far from the forces of Arawn, Lord of Death.
Princess Eilonwy "faces the unavoidable ordeal of becoming a young lady", says Alexander. Taran joins her escort to a royal court where she will continue her education, near to her ancestral home. Soon after arrival, she is kidnapped for the sorceress Achren. Taran and companions including Prince Rhun set out to rescue her.