Fourth in the series. Taran has matured and so has the story. The first novel had Taran at about 14 years old. Taran must be about 17-18 now and is yearning to find his true parentage. Eilonwy is still gone at "finishing school". Taran asks the wizard Dolbin of Taran's parentage and Dolbin says he has no clue. Taran still deeply wishes to be of royal blood, to be worthy and acceptable to a princess like Eilonwy. Taran decides to start searching (figuratively and literally). Taran and Gurgi hit the bricks. Or they would if the roads were paved.
Taran and Gurgi travel to swamp with witches from Black Cauldron. Taran is thinking to ask if the witches can tell him who he is. One says the only hope is a enchanted mirror in the mountains that shows people who they are. Taran sets off.
Adventures ensue. Taran and Gurgi meet up with the bard. Taran and company come across the dwarf who has been turned into a toad. Taran and company defeat the wizard who had enchanted the dwarf. Taran is no longer an Assistant Pig-Keeper and, since he has no name for his father, calls himself Taran the Wanderer.
Taran meets a farmer at a beaten down farm who claims he is Taran's father. Farmer says Taran's mother died in childbrith amd, unable to care for a child and operate a farm one-handed, the guy gave Taran to Dolbin as Dolbin traveled through.
Turns out farmer was lying to get Taran to stay and help with run down farm. Guy dies. Taran feels awful. He never wanted to stay. He did not want to be a farmer's son. He stayed anyway and when the farmer's life was in danger Taran still stayed rather than fleeing the farming valley at the first opportunity.
More things happen. Adventures are adventurous. Taran briefly apprentices at three trades in an effort to find what he wants to do in his life. Taran helps town fight off a bandit who bested him earlier. Taran finds mirror and sees himself. Mirror was a still pool of cave water and nothing more. Taran accepts who he is.
1. The core of the story is personal identity and value of each person as an individual. Taran runs across people who judge others based on wealth or class. He then meets people who care for none of that and are content to be themselves.
2. The concept of freedom and government. That a king who imposes his will gets nowhere and has to be wanted. Other communities have no king and cherish their freedom.
3. The value, or not, of possessions and labor. Of friendship and loyalty.