"Answer the unanswered riddle."
I just finished Harpist in the Wind, book #3 of Patricia A. McKillip's Riddle-Master Trilogy.
Reading this series a second time was nothing short of incredible for, knowing the answers to the riddles from the outset, one realizes the true depths of McKillip's cunning. It was clear from the first chapter of book one that she had this cataclysmic riddle-game planned point for point, one riddle leading into another as warriors and wraiths, harpists and shape-changers, and a farmer-prince with three stars on his face came into his power alongside a princess of An. It is, in the older and more profound sense of the word, awesome. The strictures of wizardry may teach the avoidance of death, yet those of riddlery teach that the person who flees from death often finds themself running towards it and that it is better to turn forward into the unknown rather than backward toward death. And it was riddlery that won the day.
"Beware another riddle-master."