“Is it because we’re hunters?” Dean whispered to him as he jogged along behind. “They know we’d kill them on the other side?”

The Trickster rolled his eyes. “Don’t flatter yourself. It’s because you’re mortals. Mortals only come here when we’re all in deep shit.” He stopped in front of the door at the end of the passageway and took a deep breath.

“Why are you nervous?” Sam said. “Aren’t you a god?”

The Trickster looked at him, incredulous. “So is he!” He straightened his shoulders and knocked on the door. “Besides,” he added more softly, “he scares the living daylights out of me.” At the brusque “Come!” from inside, the Trickster pushed open the door, and Sam and Dean followed him into a long, narrow, candle-lit room.

The Green Knight sat at the end of a long plank table that was lined with attendants, more fae and gnomes and dryads and knights. They all fell silent at the sight of the newcomers, and the Green Knight set down his gold flagon and got to his feet.

He was big and green, no false advertising there. His green hair flowed down to his shoulders and his green beard flowed down to his chest, his jerkin and breeches were green leather, even his skin was green as an emerald. “So,” he said. “Who are these children?”

“Sam and Dean Winchester,” the Trickster said and glanced from one to the other.

“And why have you brought them to me?”

“On her orders.”

This caused murmuring up and down the table, which the Green Knight silenced with a gesture. “What would she have me do with them? The day for sacrifices has passed.”

Sam gulped and Dean wished he had a gun. The briefcase warmed under his arm and he felt a little better.

The Trickster said, “She wants you to help them.”

The Green Knight looked none too pleased at this. “Alpha and Omega,” he said. “The beginning and the end. You’ve put us all in a precarious position, the two of you. If we’re cut off from the mortal world, we’ll continue to exist for a few centuries, but we’ll fade and grow dim until we wink entirely out of existence. And that’s only if Lucifer decides to ignore us instead of lay siege and drag us into his kingdom.”

Sam started to speak, but the Trickster made a warning noise and Sam shut his mouth. Dean took a deep breath, and then stepped up to the end of the table and laid the briefcase on it. Gasps went around through the Green Knight’s guests.

“Is that it?” the Green Knight said softly.

“Yes, sir,” Dean said. “The cup and the dish are in here. We’ve come for the sword.”

“No, no, no,” the Trickster muttered, but the Green Knight only laughed. He stood and drew a great sword from the scabbard at his waist, and laid it on the table. It shined in the dark room, and the jewels in its pommel glittered in the candlelight.

Dean unlocked the briefcase and opened it. The dish looked the same — silver and delicate — but the cup was not the same clay cup Dean knew. It was bigger and heavier, shining like beaten gold, set with jewels, a thing of beauty.

He closed the briefcase and set the cup on top of it. The cup and sword both glowed as if in recognition.

The Green Knight said in a wondering tone, “I have not seen that for many a year. It was once in my keeping, when the world was dark, but it passed on to the next guardian long ago.”

“This place was once a Grail castle?” Sam asked.

“Yes. Once.” The Green Knight gazed at the cup, lost in memories. “Those were strange and wonderful days.” He focused keen green eyes on them. “What do you know about the monster that’s following you?”

“Nothing,” Sam said.

“I saw it once,” Dean said. “It’s big and smelly.”

“A creature was stolen from its home and was made into a slave. Now this slave tracks you for its mistress and it knows the scent of your blood. Not only that, but a sorcerer has marked you — especially you, Dean.”

“I know,” Dean said quietly and took the malachite amulet from under his shirt. “I’m being looked after.”

“Yes,” the Green Knight murmured. “She would do that.”

Dean thought, This is too easy, but said, “If we can just take the sword we’ll get back to stopping the Apocalypse.”

The Trickster made another warning noise and the Green Knight burst into hearty laughter. “Nothing is that simple,” the Green Knight said. “Especially not this. First you must earn the sword. First you must prove yourselves.”

Dean sighed. “You know what? I’ve spent my entire life hunting the supernatural and I spent forty years in Hell. I don’t know what more I have to do to prove myself. And Castiel said –”

“Castiel is only an angel, boy,” the Green Knight growled, starting to rise. “I am a god.”