From the Lyric Opera of Chicago website:
Turandot, Puccini’s final opera and one of the biggest blockbusters in the repertoire, transports us to a fantasy of ancient China. There the regal, forbidding Princess Turandot poses three riddles to each prince who wishes to win her — but anyone who fails to answer correctly is executed. Prince Calaf does answer correctly, and he declares that he’s willing to die if Turandot finds out his name by dawn. The plot unfolds to music of extraordinary brilliance, including “Nessun dorma,” the most popular of all Italian tenor arias!