Harry Potter and the Half-Blood Prince

Sure enough, the greenish light seemed to be growing larger at last, and within minutes, the boat had come to a halt, bumping gently into something that Harry could not see at first, but when he raised his illuminated wand he saw that they had reached a small island of smooth rock in the center of the lake.

“Careful not to touch the water,” said Dumbledore again as Harry climbed out of the boat.

The island was no larger than Dumbledore’s office, an expanse of flat dark stone on which stood nothing but the source of that greenish light, which looked much brighter when viewed close to. Harry squinted at it; at first, he thought it was a lamp of some kind, but then he saw that the light was coming from a stone basin rather like the Pensieve, which was set on top of a pedestal.

Dumbledore approached the basin and Harry followed. Side by side, they looked down into it. The basin was full of an emerald liquid emitting that phosphorescent glow.

“What is it?” asked Harry quietly.

“I am not sure,” said Dumbledore. “Something more worrisome than blood and bodies, however.”

Dumbledore pushed back the sleeve of his robe over his blackened hand, and stretched out the tips of his burned fingers toward the surface of the potion.

“Sir, no, don’t touch—!”

“I cannot touch,” said Dumbledore, smiling faintly. “See? I cannot approach any nearer than this. You try.”

Staring, Harry put his hand into the basin and attempted to touch the potion. He met an invisible barrier that prevented him coming within an inch of it. No matter how hard he pushed, his fingers encountered nothing but what seemed to be solid and flexible air.

“Out of the way, please, Harry,” said Dumbledore.

He raised his wand and made complicated movements over the surface of the potion, murmuring soundlessly. Nothing happened, except perhaps that the potion glowed a little brighter. Harry remained silent while Dumbledore worked, but after a while Dumbledore withdrew his wand, and Harry felt it was safe to talk again.

“You think the Horcrux is in there, sir?”

“Oh yes.” Dumbledore peered more closely into the basin. Harry saw his face reflected, upside down, in the smooth surface of the green potion. “But how to reach it? This potion cannot be penetrated by hand, Vanished, parted, scooped up, or siphoned away, nor can it be Transfigured, Charmed, or otherwise made to change its nature.”

Almost absentmindedly, Dumbledore raised his wand again, twirled it once in midair, and then caught the crystal goblet that he had conjured out of nowhere.

“I can only conclude that this potion is supposed to be drunk.”

“What?” said Harry. “No!”

“Yes, I think so: Only by drinking it can I empty the basin and see what lies in its depths.”

“But what if—what if it kills you?”

“Oh, I doubt that it would work like that,” said Dumbledore easily. “Lord Voldemort would not want to kill the person who reached this island.”

Harry couldn’t believe it. Was this more of Dumbledore’s insane determination to see good in everyone?

“Sir,” said Harry, trying to keep his voice reasonable, “sir, this is Voldemort we’re—”

“I’m sorry, Harry; I should have said, he would not want to immediately kill the person who reached this island,” Dumbledore corrected himself. “He would want to keep them alive long enough to find out how they managed to penetrate so far through his defenses and, most importantly of all, why they were so intent upon emptying the basin. Do not forget that Lord Voldemort believes that he alone knows about his Horcruxes.”

Harry made to speak again, but this time Dumbledore raised his hand for silence, frowning slightly at the emerald liquid, evidently thinking hard.

“Undoubtedly,” he said, finally, “this potion must act in a way that will prevent me taking the Horcrux. It might paralyze me, cause me to forget what I am here for, create so much pain I am distracted, or render me incapable in some other way. This being the case, Harry, it will be your job to make sure I keep drinking, even if you have to tip the potion into my protesting mouth. You understand?”

Their eyes met over the basin, each pale face lit with that strange, green light. Harry did not speak. Was this why he had been invited along—so that he could force-feed Dumbledore a potion that might cause him unendurable pain?

“You remember,” said Dumbledore, “the condition on which I brought you with me?”

Harry hesitated, looking into the blue eyes that had turned green in the reflected light of the basin.

“But what if—?”

“You swore, did you not, to follow any command I gave you?”

“Yes, but—”

“I warned you, did I not, that there might be danger?”

“Yes,” said Harry, “but—”

“Well, then,” said Dumbledore, shaking back his sleeves once more and raising the empty goblet, “you have my orders.”

“Why can’t I drink the potion instead?” asked Harry desperately.

“Because I am much older, much cleverer, and much less valuable,” said Dumbledore. “Once and for all, Harry, do I have your word that you will do all in your power to make me keep drinking?”