At sunset, outside the Imperial Palace in Peking, a Mandarin reads an edict to the crowd (“Popolo di Pekino!”): any prince seeking to marry the Princess Turandot must answer three riddles. If he fails, he must die. The most recent suitor, the Prince of Persia, is to be executed at the moon’s rising; bloodthirsty citizens urge on the executioner. In the tumult, a slave girl, Liù, kneels by her aged master, who has fallen from exhaustion. A handsome youth, Calà f, recognizes the old man as his long lost father, Timur, vanquished King of Tartary. When Timur reveals that only Liù has remained faithful to him, Calà f asks why. She replies that once, long ago, Calà f smiled at her. As the sky darkens, the mob cries again for blood (“Gira la cote!”) but greets the moon with sudden fearful silence (“Per chè tarda la luna?”). The onlookers are moved when the Prince of Persia passes by, and they call upon the princess to spare him. Calà f demands that she present herself to the crowd. Turandot appears, and with a contemptuous gesture she orders that the execution proceed. Then she vanishes. As the death cry is heard from the distance, Calà f, transfixed by the beauty of the unattainable princess, strides to the gong that announces a new suitor. Suddenly Turandot’s three ministers, Ping, Pang, and Pong, materialize to discourage him (“Fermo! Che fai?”). When Timur and the tearful Liù also beg him not to risk his life (“Signore, ascolta!”), Calà f tries to comfort them (“Non piangere, Liù”); but as their pleas intensify, he strikes the fatal gong and calls Turandot’s name.