There were three things you could count on every Halloween: The streets would be crowded with people wearing terrible costumes. Someone would inevitably mistake a decorative skeleton for a real one. And Yizhou would find some way to ruin your evening.

You'd known her for centuries.

Unfortunately, immortality had done absolutely nothing to improve her personality.

Your rivalry began in an ancient kingdom over a magical artifact neither of you particularly needed. You'd both insisted you deserved it more than the other, and after a spectacularly disastrous confrontation, the artifact had vanished.

Neither of you had ever admitted to losing it.

Since then, you'd competed over everything imaginable: magical duels, treasure hunts, elaborate schemes, and even the utterly ridiculous question of who could spend the longest time living among humans without being discovered.

Yizhou had won that last competition.

She'd spent an entire decade pretending to be an ordinary village girl while secretly enchanting the local livestock.

You were still convinced she'd cheated.

Now, centuries later, she was sitting on your couch, eating your snacks, and watching a horror movie with the kind of enthusiasm usually reserved for witnessing an actual apocalypse.

"This is awful," she announced.

"You picked it."

"Because you said it was good."

"I said it was historically significant."

"You said it was a masterpiece."

"I was being polite."

Yizhou turned toward you, scandalized. "You have terrible taste."

"You once turned an entire castle purple because you lost a bet."

"And it looked fantastic."

You opened your mouth to respond, but she suddenly sat upright.

"Oh! I almost forgot."

That was never a good sign.

She reached into her coat and produced a small, intricately decorated box.

You immediately became suspicious.

"What did you do?"

"Why do you always assume I've done something?"

"Experience."

"Rude."

She placed the box on the table between you.

"I found something interesting."

You recognized the symbols carved into its lid. Your amusement disappeared. "Where did you get that?"

Yizhou's smile widened. "Wouldn't you like to know?"

You leaned forward, inspecting the markings. They were old—older than either of you, perhaps—and faintly familiar. Something about them made the air in the room feel strangely heavy.

"Ningning."

"Oh, don't use that voice."

"What did you steal?"

"I prefer acquired."

"From whom?"

"That's the exciting part." She leaned closer, lowering her voice conspiratorially. "I have no idea."

You stared at her.

She stared back.

Then she burst out laughing. "I'm joking! Mostly."

You reached for the box. Yizhou snatched it away, holding it over her head. "Ah-ah-ah! No touching. I brought it here because I need your help."

"You need my help?"

"Don't sound so pleased."

"You've spent the last three hundred years insisting you're better than me."

"I am better than you."

"Then solve it yourself."

She narrowed her eyes. For a moment, the teasing expression slipped, revealing something genuinely uneasy beneath it. "I tried."

That got your attention.

Yizhou set the box down carefully. "Whatever's inside this thing has been following me for a week. It appears in my dreams, turns up wherever I go, and keeps whispering my name when nobody else is around." She paused. "And yesterday, it called me by a name I haven't used since the Ming dynasty."

The room suddenly felt much quieter.

You looked at the box again.

Yizhou leaned back, attempting to recover her usual confidence. "So," She nudged your shoulder. "Partners?"

You folded your arms. "Why should I help you?"

She smiled sweetly. "Because if I disappear, you'll never get the satisfaction of beating me."