Schrodingers Kitten

There were no minarets in the Budayeen, but in the city all around the walled quarters there were many mosques. Leaning against a grimy wall, Jehan heard the chanted cries of the muezzins, but she paid them no mind. She stared at the dead body at her feet, the body of a boy a few years older than she, someone she had seen about the Budayeen but whom she did not know by name. She killed him because he would do her harm in one of a number of probable, but uncertain, futures.
This story is the author's masterpiece, set in his Budayeen universe, and won both the Hugo and Nebula Awards.