But she was a Yazidi girl, and so she was raped for weeks by the fighters, in dim tents stinking of sweat and old blood, before being trucked to the killing sands outside the ancient city.

They told her to convert, but she refused.

They told her of the consequences. She accepted them.

Allah is Lord of all worlds, they said; and though she does not believe they speak for God, she imagines that there could really be other worlds than this.

There are broken human teeth on the floor of the cell. It’s too dark to see, but she can feel their shape with her fingertips.

She remembers Ahmad-Hafiz’s teeth when he smiled: so nicely shaped, so white.

She’d met Ahmad-Hafiz, a Kurmanji-speaking Kurd, only a year before, on her first ever trip to Baghdad to tour several universities. Her village had resolved to fund her study in the capital, pending her acceptance by an institution there. Ahmad-Hafiz was a physics Ph.D. student at the University of Baghdad, who’d shown her around the College of Science.

He was fascinated, he told her, by quantum mechanics. She asked him why, never having heard of them but delighted by his attention upon her.

“Because of the possibilities,” he’d said.

“What possibilities?”

“That in reality there are more worlds than this. An infinite number.”

“What kind of worlds?”

“Parallels,” said Ahmad-Hafiz, and refilled her tea cup. He liked tea, even with his white teeth. “Let’s take Cecil the lion, for instance.”

“Cecil?”

“It was a lion killed in Africa a month back. A popular lion, I guess. People are calling for the hunter’s blood.”

“Because of a lion?”

“Well it was special enough, after all, to have a name. Anyway, imagine the hunter is there with his bow, and he’s about to shoot.” Ahmad-Hafiz mimed pulling back a bowstring. “And roar! A lioness suddenly leaps on him from behind, killing him!”

“Oh . . .”

“Now that didn’t happen. But consider, just for fun, that there could have been this lioness nearby. She smells the hunter and a thought is about to spark in her brain, either to attack or not to attack. But if we accept what’s called the Everett interpretation, both of those sparks occur, and from there the world splits into two. In one, the hunter dies and Cecil lives; in the other—the world you and I inhabitthe opposite happens. Those two worlds branch away from each other, forever undetectable.”

“But is it possible?” she asked, mystified.

Ahmad-Hafiz offered his gleaming smile. “Well, it’s theoretical,” he said. “Nothing is certain.”

The door of the cell slides open. She places the broken teeth, belonging to some forgotten man or woman, in a row where the wall meets the floor. A hood is placed over her head and she is led outside. She is slapped when she does not stand in the right place, though she can’t see the line she is meant to be a part of. She can’t see anything. Her ear grows hot where she was struck. Her heart thrums violently behind her ribs.

The hammers of multiple guns are drawn back. Her bladder wants to let go, but she fights to keep from dirtying herself, determined not to let them know her fear.

She waits for her lioness.

She waits to find out which world this is.

She is buried with the others in a shallow grave.