“Thank you,” said Harry gratefully, but Dumbledore had already turned his attention back to the solid cave wall. He did not try any more magic, but simply stood there staring at it intently, as though something extremely interesting was written on it. Harry stayed quite still; he did not want to break Dumbledore’s concentration.
Then, after two solid minutes, Dumbledore said quietly, “Oh, surely not. So crude.”
“What is it, Professor?”
“I rather think,” said Dumbledore, putting his uninjured hand inside his robes and drawing out a short silver knife of the kind Harry used to chop potion ingredients, “that we are required to make payment to pass.”
“Payment?” said Harry. “You’ve got to give the door something?”
“Yes,” said Dumbledore. “Blood, if I am not much mistaken.”
“Blood?”
“I said it was crude,” said Dumbledore, who sounded disdainful, even disappointed, as though Voldemort had fallen short of higher standards Dumbledore expected. “The idea, as I am sure you will have gathered, is that your enemy must weaken him– or herself to enter. Once again, Lord Voldemort fails to grasp that there are much more terrible things than physical injury.”
“Yeah, but still, if you can avoid it…” said Harry, who had experienced enough pain not to be keen for more.
“Sometimes, however, it is unavoidable,” said Dumbledore, shaking back the sleeve of his robes and exposing the forearm of his injured hand.
“Professor!” protested Harry, hurrying forward as Dumbledore raised his knife. “I’ll do it, I’m—”
He did not know what he was going to say—younger, fitter? But Dumbledore merely smiled. There was a flash of silver, and a spurt of scarlet; the rock face was peppered with dark, glistening drops.
“You are very kind, Harry,” said Dumbledore, now passing the tip of his wand over the deep cut he had made in his own arm, so that it healed instantly, just as Snape had healed Malfoy’s wound, “But your blood is worth more than mine. Ah, that seems to have done the trick, doesn’t it?”
The blazing silver outline of an arch had appeared in the wall once more, and this time it did not fade away: The blood-spattered rock within it simply vanished, leaving an opening into what seemed total darkness.
“After me, I think,” said Dumbledore, and he walked through the archway with Harry on his heels, lighting his own wand hastily as he went.
An eerie sight met their eyes: They were standing on the edge of a great black lake, so vast that Harry could not make out the distant banks, in a cavern so high that the ceiling too was out of sight. A misty greenish light shone far away in what looked like the middle of the lake; it was reflected in the completely still water below. The greenish glow and the light from the two wands were the only things that broke the otherwise velvety blackness, though their rays did not penetrate as far as Harry would have expected. The darkness was somehow denser than normal darkness.
“Let us walk,” said Dumbledore quietly. “Be very careful not to step into the water. Stay close to me.”
He set off around the edge of the lake, and Harry followed close behind him. Their footsteps made echoing, slapping sounds on the narrow rim of rock that surrounded the water. On and on they walked, but the view did not vary: on one side of them, the rough cavern wall, on the other, the boundless expanse of smooth, glassy blackness, in the very middle of which was that mysterious greenish glow. Harry found the place and the silence oppressive, unnerving.
“Professor?” he said finally. “Do you think the Horcrux is here?”
“Oh yes,” said Dumbledore. “Yes, I’m sure it is. The question is, how do we get to it?”
“We couldn’t… we couldn’t just try a Summoning Charm?” Harry said, sure that it was a stupid suggestion. But he was much keener than he was prepared to admit on getting out of this place as soon as possible.
“Certainly we could,” said Dumbledore, stopping so suddenly that Harry almost walked into him. “Why don’t you do it?”
“Me? Oh… okay…” Harry had not expected this, but cleared his throat and said loudly, wand aloft, “Accio Horcrux!”
With a noise like an explosion, something very large and pale erupted out of the dark water some twenty feet away; before Harry could see what it was, it had vanished again with a crashing splash that made great, deep ripples on the mirrored surface. Harry leapt backward in shock and hit the wall; his heart was still thundering as he turned to Dumbledore.
“What was that?”
“Something, I think, that is ready to respond should we attempt to seize the Horcrux.”
Harry looked back at the water. The surface of the lake was once more shining black glass: The ripples had vanished unnaturally fast; Harry’s heart, however, was still pounding.
“Did you think that would happen, sir?”
“I thought something would happen if we made an obvious attempt to get our hands on the Horcrux. That was a very good idea, Harry; much the simplest way of finding out what we are facing.”
“But we don’t know what the thing was,” said Harry, looking at the sinisterly smooth water.
“What the things are, you mean,” said Dumbledore. “I doubt very much that there is only one of them. Shall we walk on?”
“Professor?”
“Yes, Harry?”
“Do you think we’re going to have to go into the lake?”
“Into it? Only if we are very unfortunate.”
“You don’t think the Horcrux is at the bottom?”
“Oh no… I think the Horcrux is in the middle.”
And Dumbledore pointed toward the misty green light in the center of the lake.
“So we’re going to have to cross the lake to get to it?”
“Yes, I think so.”
Harry did not say anything. His thoughts were all of water monsters, of giant serpents, of demons, kelpies, and sprites…
“Aha,” said Dumbledore, and he stopped again; this time, Harry really did walk into him; for a moment he toppled on the edge of the dark water, and Dumbledore’s uninjured hand closed tightly around his upper arm, pulling him back. “So sorry, Harry, I should have given warning. Stand back against the wall, please; I think I have found the place.”
Harry had no idea what Dumbledore meant; this patch of dark bank was exactly like every other bit as far as he could tell, but Dumbledore seemed to have detected something special about it. This time he was running his hand, not over the rocky wall, but through the thin air, as though expecting to find and grip something invisible.
“Oho,” said Dumbledore happily, seconds later. His hand had closed in midair upon something Harry could not see. Dumbledore moved closer to the water; Harry watched nervously as the tips of Dumbledore’s buckled shoes found the utmost edge of the rock rim. Keeping his hand clenched in midair, Dumbledore raised his wand with the other and tapped his fist with the point.
Immediately a thick coppery green chain appeared out of thin air, extending from the depths of the water into Dumbledore’s clenched hand. Dumbledore tapped the chain, which began to slide through his fist like a snake, coiling itself on the ground with a clinking sound that echoed noisily off the rocky walls, pulling something from the depths of the black water. Harry gasped as the ghostly prow of a tiny boat broke the surface, glowing as green as the chain, and floated, with barely a ripple, toward the place on the bank where Harry and Dumbledore stood.
“How did you know that was there?” Harry asked in astonishment.
“Magic always leaves traces,” said Dumbledore, as the boat hit the bank with a gentle bump, “sometimes very distinctive traces. I taught Tom Riddle. I know his style.”