The fight not over, Taran and his companions plot to destroy the Black Cauldron, the instrument that Arawn, Lord of the Underworld, uses to make his deathless warriors. Resurrected from dead bodies, the deathless warriors serve him and cannot be killed.
The Sons of Don band together to steal the Black Cauldron from Arawn so that he cannot make more warriors for his army, but things do not quite go as planned. So Taran is forced to make decisions about whether or not to continue the quest.
Morality
Good and evil are clearly represented. While there are the greater issues of good and evil, there is also an inward struggle as Taran, among others, battles his own desire for honor and glory.
Spiritual Content
These stories were based on Welsh Mythology. The whole idea of making "deathless" warriors with the use of a cauldron can be seen as quite spiritual. There is some magic represented, though it is not a central theme. The magic is more reminiscent of The Hobbit than Harry Potter.
Violence
There are some fighting scenes that involve sword play. There are no graphic descriptions. Characters, both good and bad, do die.
Drug and Alcohol Content
None.
Sexual Content
None.
Crude or Profane Language or Content
None.
Conclusion
Of the five books in the series, this one is my second favorite. There is tremendous character growth throughout the story. While Alexander did not purposefully weave Christian allegory into his stories, some can be found. For adult Tolkien fans with children who are not old enough for The Lord of the Rings, this and the previous book, The Book of Three, are excellent introductions into epic fantasy.