Moaning Myrtle's bathroom remained out of order. Snape pushed the door open, and he and Harry entered with silent steps. No sign of Moaning Myrtle, who should be out on a stroll through the plumbing.

They went to the sink and the tap with the carved snake.

"Open up," said Harry in Parseltongue.

The tap glowed intensely and started spinning. The sink moved then, exposing the broad pipe.

"I'll go first. Wait a while before coming in, or you will fall on my head," said Snape, pushing Harry away and jumping into the pipe. Cold, damp darkness swallowed him before the vertiginous fall. Endless seconds passed until he landed on the wet floor of the stone tunnel. "Lumos!"

Soon Harry landed beside him.

They walked into the tunnel, enveloped in shadows. Rats ran in all directions, fleeing their steps.

At last, they got to the wall with the two entwined serpents sculpted in it. Their emerald eyes glinted. Harry stepped forward and hissed, "Open up."

The serpents parted, revealing the inside of the Chamber.

With utmost caution, they entered. The same eerie, greenish gloom, the sinuous pillars. Everything was just as Harry had found in his second year. Except, he hoped, for the Basilisk. Snape looked at everything with such interest and attention that Harry couldn't help asking, "How do you feel, being inside Slytherin's sanctuary? Is it an old dream coming true for you?"

"Isn't it ironic? When I was your age, I would dream I was the Heir of Slytherin! Now a Gryffindor guides me to Salazar's sanctuary! I hate you, Harry Potter, more and more!"

Harry gave him a shining smile.

They approached the giant statue of Salazar. The simian face, the long beard, the imperial posture.

"Was the Basilisk in there?" asked Snape.

"Yeah. It came out through Salazar's mouth."

"Frightening, but I wish I could have seen it! Why did you have to bring that useless Lockhart and not me?"

"Because you were the one who told him to come, remember? And at the time I was more afraid of you than of a Basilisk." The green eyes had an amused gleam as they met dark ones. "As if you would have let us come!"

"Of course I wouldn't! A twelve-year-old boy facing Tom Riddle and a Basilisk!"

"Oh, the Headmaster knew I would come. He all but sent me here."

"It's frustrating, downright exasperating. He always leaves us hanging, trying to guess his strategy." Snape gazed at Harry inquisitively. "You think he let you come here in order to... test you?"

"To test me or teach me something, I'm not so sure."

"And what did you learn from it?"

"Er... Something about choices. That I'm responsible for my choices. But the example he gave me, I thought it was brilliant at the time, now I think it's so stupid. He said the reason the Hat put me in Gryffindor and not in Slytherin was because I chose so. Only I knew nothing about Slytherin or Gryffindor then, I was acting on sheer prejudice. I don't see anything great in it."

"But when you were twelve, it was important for you to know... or to believe... that you had chosen correctly."

The two wizards looked at each other for a brief moment. Harry began to believe they were reaching a higher level of understanding, above all the silly prejudices such as the childish, artificial separation of the Houses.

"What do we do now?" asked Harry. "Where should we start searching for the crypt?"

"I would start with the statue. That's why I told you to bring your broom. If the Basilisk was inside it, maybe it was guarding something of value."

They walked closer and around the statue, studying it carefully as they looked for cracks or serpents, probing it for moveable parts. They made a full circle around it without finding anything that could offer them access to some place else.

"I was afraid of that. We have to enter through the mouth," Snape stated. "You know the password to open it, don't you?"

"Ugh. I'm not saying what Tom Riddle said. Over my dead body."

"What did he say? Whisper it in my ear."

Harry murmured, "'Speak to me, Slytherin, greatest of the Hogwarts Four.'"

"That's just more nonsense from that insane megalomaniac. Just ask him to open his mouth and be done with it."

"Speak to me, Slytherin, powerful wizard!" Harry hissed.

The statue's mouth started opening.

"I'll go first," said Snape. "If a Basilisk fits in there, a broom flying horizontally is likely to fit as well. But we don't know if two brooms will."

The two of them mounted on their brooms and took off. Snape went straight to the mouth and, slowly, flew in. He found himself in the most absolute darkness. "Lumos!" Then he shouted at Harry, "I am going to try to spiral down. Follow me."

The descent seemed to go on forever. Harry was starting to get bored when at last the space expanded around them and he managed to hover at the same level as Snape. The walls surrounding them were made of pure crystal, and emitted a thousand glints.

"By Merlin!" Snape exclaimed.

"This crypt must be in the centre of the Earth, considering how far we came down."

As they rested their feet on solid rock, they could not believe it. They were surrounded by crystals, in a huge crypt that extended into a sombre, apparently curved tunnel.

"That Slytherin fellow really wasn't an ordinary wizard, was he?" Harry commented.

Snape stared at Harry with his nose in the air and that expression of his that spelled, 'Kiss the floor where I'm standing, foolish Gryffindor'. "We should look for Slytherin's altar."

"It must be through that tunnel over there."

"Lumos!" said Snape once more, resigned.

Through rainbow reflections that spread everywhere, they walked until a closed double door, with an ouroborus (the serpent eating its own tail) serving as lock.

"This is getting rather monotonous," Snape commented, indicating the serpent to Harry.

"Open up!"

However, nothing happened. Snape moved forward and said, "Alohomora!"

Nothing. Snape tried all the spells he knew, in vain.

"Let's try Alohomora together," Harry suggested.

Snape sighed, sceptical. He looked at Harry, who pointed his wand and started counting, "Three, two, one..."

"Alohomora!"

The ouroborus unlocked and the door opened. They stepped inside and found themselves before the scene described by Salazar in his Manuscript: the obelisks, the retable, the candelabra, the altar with a chalice on the centre.

"I told you, the Grail is lonely and ruined."

"Sev... All that stuff must have some meaning. They must have some use."

They had nothing to decipher anymore, their Wednesday night meetings should have been finished, but then, who would know that? Dumbledore? All right, he would know soon. If he didn't know already from his own obscure resources.

It was the afternoon of the same morning when they had entered the Chamber of Secrets, and they were back in Snape's office. They had decided to leave Slytherin's altar untouched. Snape had told Harry that it was too dangerous to take magical objects outside the Chamber without a deeper study of them. Those objects could be trap triggers, like Riddle's Diary. Furthermore, they hadn't been able to move the chalice, take it from its place - it was as if it had been nailed to the altar. So that was it, they had found the Grail, but didn't know what to do with it...

"Let's talk to the Headmaster," said Snape, defeated. He hated to admit he needed the old wizard. "Maybe he knows."

"You what?" Dumbledore's eyes widened. "You have found the Grail and don't know what it means?" The old wizard let out the most thunderous chortle. He doubled up in his purple stuffed chair and seemed about to roll on the floor.

Snape and Harry looked at each other, at first surprised, then angry. Very angry.

"Albus, get a hold of yourself!"

The Headmaster needed a couple of moments more to regain his composure. "Ah, ah. Boys, you are so funny."

"I don't see what's so funny about it," Harry stated.

Snape was too shocked to say anything.

"My boys, you have seen the dream of any wizard come true: you have found the Grail." Dumbledore had to control himself not to start laughing again. "Would you like a sherbet lemon?"

"No, Albus, please quit torturing us. Speak up."

"Calm down, boys. As I was saying, you have made the biggest of all dreams come true. That's it."

Snape and Harry exchanged glances once more.

"So what?" asked Harry, more irritated by the minute.

"So the last thing you should be asking at a time like this is 'so what'! Celebrate or forget it, do something, just don't ask 'so what'."

"Albus!"

"I'm not going to tell you the joke. If I do, now, it won't be funny at all!"

"Joke, but what joke? We came here to ask you a question and you keep laughing in our faces."

"Enough. Let's go, Potter," said Snape, indignant.

"Er," said Harry as they passed by the gargoyle. "I'm going to talk to Hermione. She might be able to help. Wanna come with me?"

Snape hesitated. He had no wish to talk to the Gryffindor know-it-all. He felt no sympathy for her, and he had been humiliated enough for one day. But he also couldn't stand the thought of Harry learning something before him and possibly not telling him later.

"Take her to my office." At least there he would be in his territory. He wouldn't feel so helpless.

Along with Harry, Hermione stepped inside the Potions master's office with a look of lively curiosity in her face.

"Miss Granger."

"Good afternoon, Professor Snape."

"Take a seat on the sofa and make yourselves comfortable. I'll bring the tea."

Hermione looked at Harry, frowning. Harry just smiled and fetched Ceci to introduce her to Hermione. Ceci was over 3 feet long now.

"So this is Ceci! I had never seen a golden boa. She's so pretty."

At first Hermione was afraid of holding her, but soon she let the snake coil around her arm.

Snape poured tea for all of them and placed a dish with biscuits in the centre of the low table.

Harry - interrupted by Snape many times - told Hermione the whole story about their research. Hermione's eyes sparkled. She had always been interested in Hogwarts' history, had read all the books she had found about it, and she couldn't resist an intellectual challenge. As they got to the end of the story, those darting eyes turned from her friend to the teacher and then back to her friend, incredulous.

"The Grail? Could it really be the Grail?" she asked, sitting on the edge of the sofa, as if impatient, as if ready to get up and... do something. Watching her, Harry grinned, recognising the Gryffindor urge to act that often got the best over the critical, intellectual posture that would lead anyone to label her a Ravenclaw.

"That's the problem, Hermione, how can we know?"

"Miss Granger, we trusted Slytherin's word and found a chalice in the place where he said the Grail would be. But we cannot verify if it is the Grail or not. Slytherin might have been wrong. He might be lying. Riddle might have taken the Grail and left an ordinary chalice in its place. Anyway. There are many possibilities."

"Hermione, what we want to know is... what is the Grail for?"

"Professor Snape doesn't know?"

Snape glared at her as if he were about to cast Avada Kedavra on both of them. "If you are asking me if I'm familiar with the legends about the Grail, I obviously am. What I would like to know is whether that instrument has any use for us nowadays."

"Ah, yes. Let's consider what we know about the Grail. In the monastic version of history..."

"...the Grail is associated with Christ's Passion," Snape finished.

Harry sighed. That was turning into a duel between know-it-alls.

"Exactly. The Grail is the chalice of the Last Supper, the chalice that received Christ's blood as he was taken from the cross," Hermione continued.

"It is also said that the Grail was brought from heaven by the neutral angels," Severus commented.

"Neutral angels?" asked Harry.

"During the heavenly war between God and Satan, between good and evil," Hermione explained, "some angelic hosts took Satan's side, and others, God's. The Grail was brought through the middle path by the neutral angels. The Grail represents the spiritual path that crosses the bridge between opposing pairs, between fear and longing, good and evil. The Grail represents the accomplishment of the highest spiritual potentials of human conscience."

Harry looked at the tapestry of the Lion and the Serpent over the fireplace, right before him. Severus followed his gaze. "I would say the Christian separation between matter and spirit has in fact castrated nature. Could the Grail have been an attempt of reunification?" Snape suggested.

"I'd rather say the Grail has become the symbol of an authentic life, of a life that moves between opposing pairs, good and evil, light and darkness. If all act in this life sets out opposing pairs, the best we can do is to lean toward light, toward harmony, creating relationships that will result in compassion, comprehension. That's what the Grail is all about."

"If that is what we've found..." said Harry.

Green eyes met dark ones.

"If that is what you've found, then it's something really precious," Hermione concluded.