By Patricia McKillip.
A superbly told story with a lot of humour (maybe it's only on the re-reading); the downside, I guess, is that the threads in the end are tied up so neatly there is not much to speculate about. It's a little self-contained chunk of story.
For those who want to know, the story starts out with Brenden Vetch, who is invited by Od to garden at her school of magic in the city of Kelior to the south. "Look for the door under the shoe", she says. Only when he arrives at the school does he find out that no one there has heard or seen Od for 19 years.
The other thread is the traveling magician Tyramin, who has also come to Kelior. Is his mysterious magic real or merely illusion? No one seems to know where to find him or who he is; surely he can't be the same Tyramin the princess's great-grandmother remembers! When the gardener disappears into the city's Twilight Quarter, the king's suspicions about uncontrolled magic just about boil over... something has to give.
I actually find Tyramin a more sympathetic character than Brenden. He is exactly what he appears to be even though no one sees it. (There is nothing more to say without spoiling it.)
There are a lot of laugh-out-loud moments of humor, such as when Brenden flowers (literally) while he's trying to imagine what kind of land a cactus he finds in his garden is from, or when Sulys's great grandmother says things she supposedly meant only to think.
The labyrinth beneath Od's school, students who ask too many questions, a gardener with more magic than he knows what to do with, an unruly princess, and everything come together to form a wonderful, neat, happy tale. (Wow, I'm gushing.) Still, as I said, it ends so neatly there isn't too much to wonder about in it. It at least gives the illusion that everything is explained or not worth explaining. The magician's daughter and the grandmother are the most memorable characters; I barely remembered the rest when I came back to start rereading it.