Harry slowly pushed the door of the girls' lavatory; it opened with a creak.

"The entrance is in here?" Draco did not seem convinced.

"Sure," Harry said. "All you have to do is say something in Parseltongue--" But before he could demonstrate his fluency in snake-language, Moaning Myrtle swooped down on them.

"Hello, Harry," she said sweetly.

"Hi, Myrtle," Harry replied.

"Oh, and Draco, too!" She sidled up next to him with a girlish giggle. Hermione snorted with laughter.

"No offense, Myrtle," Harry said gingerly, "but we're really not here to chat."

Her innocent smile turned into a scowl. "Of course," she sniffed. "No one cares to talk to Myrtle..."

"We'll come back," promised Hermione hastily. "Won't we?" She looked encouragingly at Draco and Harry.

Reluctantly, they nodded.

Mollified, Myrtle floated back to the U-bend, while Harry whispered a command in Parseltongue. The sinks parted, revealing the opening to the Chamber.

"Who's going first?" asked Hermione.

Without a word, Draco jumped into the hole. "Bloody hell, it's nasty down here," he called, and Hermione jumped in after him, lighting her wand. Ron followed.

"Go ahead," Harry said.

"I'm not too sure about this," Zacharias said.

"It's fine. Just go."

Zacharias jumped, with Melody close behind him.

"Hold my hand?" Ginny squeaked.

Harry clasped her fingers in his, and they went sliding down the grimy, disgusting pipe, landing with a thud on the Chamber's floor.

Ginny clung tightly to Harry as they got to their feet. "Lumos," she whispered, peering around at the walls.

"This way," Harry directed, leading the troop deeper into the cave.

"Uh, Harry," Ron spoke up, "how d'you suppose we get through this?" He nodded at the mountain of rubble that they'd left behind in their second year.

Hermione rolled her eyes. "Reducto!"

Harry walked through the hole that Hermione had cleared and set eyes on the emerald-eyed serpents. "Open for us," he commanded, but his voice came out in the same whisper-silk voice.

"Ugh. What smells?" Zacharias said disgustedly, putting his hand over his nose. Stepping over the threshold, he came face-to-face with a dead, rotting Basilisk. Melody shrieked.

"They just left it down here?" Hermione was nauseated.

"What is it?" After her initial shock, Melody was intrigued. She stepped up to get a closer look.

"A dead basilisk," said Hermione.

Harry averted his eyes. "Water," he coughed. "Look for water."

Hermione set her wand in her open palm. "Point me," she said, and the wand snapped to attention.

"This way," she said, leading them due west.

"Why?" Melody wanted to know.

"In Greek tradition," Hermione said, "water is associated with many things, one of which is the western point of the compass. If Voldemort really did hide the cup down here, I think it's a pretty safe bet that he's following these old superstitions." The light from her wand revealed a large tile set into the floor, inlaid with the shape of an upside-down triangle. "See?" She gestured at it. "That's the alchemical symbol for water."

"How do you know all this?" Draco knelt to run his fingers over the triangle.

"I thought about becoming an alchemist," Hermione said matter-of-factly.

"Hey," Draco said, "there's air coming from the cracks."

Harry considered Ron. "Think it's under there?"

"There's only one way to find out." Hermione pointed her wand at the tile. "Wingardium leviosa."

Up came the large stone, and Hermione levitated it safely to the side.

"Not another tunnel, I hope." Melody shuddered.

"Nope," Zacharias said, peering over the edge. "Stairs. "C'mon."

The companions inched down the staircase into a greenish dungeon-looking corridor. The moment they stepped off the last stair, the entire corridor went black, and the scrape of the stone as it returned to place came as a dull echo above their heads.

"Lumos," Harry said firmly, shaking his wand. Nothing happened. "Lumos!"

Ginny clung to him tighter than ever. "What's going on?" Her voice was tight and high-pitched.

But Hermione laughed. "Well played, Voldemort," she said.

"What do you mean?" Ron snapped.

"He's shut our air supply off," Hermione explained.

"Well, that's something to laugh about!" Zacharias shrieked.

Hermione sighed. "We just have to give birth to air," she said, as if it was the most obvious solution in the world.

If Ron could have seen her, he would have slapped her. "What?"

"The Minor Arcana," Hermione said impatiently. "Don't you see?"

"Apparently not!" Harry shouted.

"Melody has Ravenclaw's wand. Zacharias is Hepzibah Smith's grandson; the Voldemort is the heir of Slytherin. So, Ron--"

"You're saying I'm descended from Gryffindor?" he squeaked.

"Well, you have to be, don't you?"

He gulped. "So what do I do?"

"Air is the element of the swords," Hermione said. "Air gives birth to fire, which gives birth to water, which gives birth to earth."

"That's beautiful, Hermione, but it doesn't help me much!"

"What about the hat?" Draco said loudly.

Ginny gave a little start. "I have it," she said, sticking it on her hand to extend it to her brother; instead, she rammed her knuckles into the hilt of a sword. "Oww," she said softly, and pulled a ruby-encrusted sword from the hat.

At once, the room became a brilliant pastel blue, and the dull, damp air turned into a fresh, intoxicating breeze. The breeze quickly turned into a brisk wind, and the wind began to pick up.

"Give it to Melody!" Hermione yelled.

Ginny handed the hat to Melody. Grasping the edge of it, she thrust her arm inside and pulled out her own wand. Flames began to lick the sides of the room with urgency. "Here!" yelped Melody, thrusting it at Zacharias.

He reached inside and, with a deep breath, removed a long, knobbly walking stick. Water began to spill from the cracks in the ceiling.

"We don't have an heir of Slytherin," Hermione noted.

"Thanks for that," Ron said caustically. "Now what?" The flood was already up to his ankles.

"You try," Zacharias suggested, tossing the hat to Draco. He reached in; nothing.

"This damn Hat almost put you in Slytherin," Draco said, handing it to Harry. "Maybe you can get it to believe you're a true heir."

Harry sighed, closed his eyes, and plunged his hand into the hat. When he brought it out, he was holding a live snake, which he immediately dropped onto the ground; the floor hardened and the water washed away and green grass carpeted the stone floor.

"Not bad, Potter," Draco approved smugly. "Now what?"

But his question was about to be answered. A sapling had just sprouted from the ground. They watched as it grew, unfurling leaves, stretching branches out over the cave. A hollow appeared in the trunk, and inside sat a cup, shining in the soft light.

"There it is," Zacharias said in awe. He reached for it, but was immediately knocked to the ground. Next, Ginny tried, but she was likewise thrown to the floor.

"No," Draco said, "no. It's all of you together. This is what the Sorting Hat has been telling us about since the beginning."

"The houses united," Harry said, still wondering why he was able to represent Slytherin.

The four of them reached their hands into the hollow at once, and placed their hands around the rim, bringing it out into the light.

"My dad will be ecstatic," Zacharias said, raptly gazing at the antique cup. He looked over at Harry. "I-- do you have to destroy it?"

Harry shook his head. "No," he replied. "I only have to rid it of its evil."