The High King, by Lloyd Alexander

This book is about a boy named Taran who destroys evil magic. This time we meet Taran in Caer Dallben, receiving a warning message from Gwydion, saying that the power-sword Dyrnwyn is gone. Taran and everybody else in Caer Dallben, except for Dallben, round up a war-band. Taran, under the Banner of the White Pig, gets many common folk to join him. They journey to Caer Dathyl and do battle, but lose, destroying Caer Dathyl. Taran and his band of common folk delay the Cauldron-Born from coming ot Annuvin, but they don’t slow the Cauldron-Born enough. All would be a disaster if Taran had not found the sword Dyrnwyn and unsheathed it. Taran strikes down the Lord of Annuvin, then sets out to make the world better.

This was the fifth and last book in the Chronicles of Prydain series. I love it. It is good for all ages, but especially happy-yet-strange ending lovers.