The story continues after Wicked's. The Wizard of Oz has fallen from power and the two Wicked Witches have been killed by a child from another world. A woman finds a young man beaten and near death by the side of the road. The man is brought to the Cloister of Saint Glinda in the Shale Shallows where the Superior Maunt recognizes him as Liir, the young boy who left the Cloister with Elphaba a decade ago.
Son of a Witch was released ten years after the first novel. It's dedicated to the musical cast of Wicked, which was released a few years prior.
A Son of a Witch provides examples of:
- Bi the Way: Liir.
- Foreshadowing: One particular example said by Trism to Liir: "Are you just slow, or are you falling in love with me?"
- The Lost Lenore: Even years later, Glinda breaks down in tears when reminded of her "Elphie".
- Ship Tease: At the end of Son of a Witch, Liir is separated from both of his love interests, Trism and Candle, but only due to circumstances - he's open to a relationship with either. The third book is entirely silent on the matter, as they don't appear, though the family tree at the beginning shows relationships out of wedlock to both of them. The fourth book would appear to finally resolve the matter, with Liir married to Candle, and Trism assumed to have betrayed the both of them. But by the end of the book, Candle has left Liir indefinitely, and while his reunion with Trism was fraught with argument, it was also heavy in Unresolved Sexual Tension, revealing that their attraction hasn't faded. The book ends with Liir alone, stating that his door is open to either of them should they choose to come back. Since this leaves open any option a fan prefers, including a One True Threesome, it can come off as fanfic baiting.
- Time Skip: Son of a Witch starts out with Liir still a child only a little older than he was in Wicked, but quickly skips to his early-to-mid twenties.
- Wham Line: At the end of Son of a Witch: "He took her to the doorway and held her up in the warm rain. She cleaned up green." Notably (and frustratingly), this is the very last line in the book.
- Yaoi Guys: In the second book Liir and Trism.