Firebelly by John Murray Lewis
There was a time when he went by Little Zhong Kui—when he was China's most famous fighter of ghosts and demons. But for the venerable Shi Shen, apothecary and scholar, those days were long gone, and his enemies now were only the feeble ailments of body and mind.
That is, until the night that a mysterious illness gripped Shen's old friend, the merchant Yang Tao, and filled his mind with visions of a hideous fire-bellied toad.
Madame Yang sent for Shen. He let himself into Tao's room.
"Master Shi!" Tao croaked. "Ah, I feared it was my wife."
They spoke a little while of close calls, lost loves, and other misadventures. As Tao reminisced, Shen laid out various medicines from his satchel. When this was done he said, "Tao, do you remember Chengdu?"
A glassy look fell over Tao's eyes. "Of course—the toad-gu. A messy affair. That was the last time you called yourself 'Zhong Kui'... Why do you ask, Shen?"
"Isn't it obvious, Tao?"
"Ha! So, you've figured it out: the gu has returned for me."
"The toad-sorcerer eluded us in Chengdu, Tao. Now the proud fool's revealed himself again, and we have another chance to finish the job."
Tao sighed. "Forget it, Shen. I know who the sorcerer is."
"A charming Miao girl. A courtesan at the House of Spring Blossoms."
"I can't betray her, Shen. The gu's power over me is too strong." Tao clutched at Shen's sleeve. "But all's not lost—not yet. I have a secret sum of money. If it doesn't fall into the sorceress's hands, it will support my family—"
"What are you suggesting?"
"You know! The sap of the Poison Arrow Tree: death to man and spirit alike. One drop and I will drag this demon inside me to Yanluo Wang's court."
"And let the sorceress go free? Her secrets will die with the gu! Take another draught instead. Myoga will weaken the spirit; an emetic will coax it out..."
"What then, Shen? The spirit is strong, and you are old. Remember that the toad-gu is a spirit of greed, and that you are as greedy for past glory as I was for the attention of a beautiful girl."
Shen saw that Yang Tao would not be persuaded. "Very well," he said, and handed Tao a vial of viscous, murky-gold liquid.
Tao drank it, thanked Shen, and closed his eyes.
Shen muttered an apology as Tao gagged—as his face contorted in fear and rage—as the myoga mixture seeped through his body—
Moments later, when Madame Yang entered the bedroom, tea tray in hand, she found her husband asleep, damp with sweat, snoring. Shen was placing his medicines back inside his satchel.
"Is my husband cured, Master Shi?"
"The worst has passed," he said, and turned for the door.
Halfway down the hall, he coughed—though to Madame Yang, it sounded almost like a croak.