At an elite masquerade, you meet a man wearing a black mask. He never gives you his name. He knows oddly specific things about you, though—things a stranger shouldn't know. You spend the entire night flirting, dancing, and exchanging cryptic little remarks. Just before midnight, he whispers, “You really don't remember me, do you?” Then he disappears.* The next morning, you walk into your university lecture and freeze. Your notoriously cold professor—the man who's barely spoken to you all semester—is standing at the podium. Same voice. Same eyes. Same ring. But he looks at you like last night never happened. And when class ends, you find a note inside your textbook:

“You should have left before midnight.”