“Voldemort needed an elf?” Harry repeated, looking around at Ron and Hermione, who looked just as puzzled as he did.
“Oh yes,” moaned Kreacher. “And Master Regulus had volunteered Kreacher. It was an honor, said Master Regulus, an honor for him and for Kreacher, who must be sure to do whatever the Dark Lord ordered him to do… and then to c-come home.”
Kreacher rocked still faster, his breath coming in sobs.
“So Kreacher went to the Dark Lord. The Dark Lord did not tell Kreacher what they were to do, but took Kreacher with him to a cave beside the sea. And beyond the cave was a cavern, and in the cavern was a great black lake…”
The hairs on the back of Harry’s neck stood up. Kreacher’s croaking voice seemed to come to him from across the dark water. He saw what had happened as clearly as though he had been present.
“…There was a boat…”
Of course there had been a boat; Harry knew the boat, ghostly green and tiny, bewitched so as to carry one wizard and one victim toward the island in the center. This, then, was how Voldemort had tested the defenses surrounding the Horcrux, by borrowing a disposable creature, a house-elf…
“There was a b-basin full of potion on the island. The D-Dark Lord made Kreacher drink it…”
The elf quaked from head to foot.
“Kreacher drank, and as he drank he saw terrible thing… Kreacher’s insides burned… Kreacher cried for Master Regulus to save him, he cried for his Mistress Black, but the Dark Lord only laughed… He made Kreacher drink all the potion… He dropped a locket into the empty basin… He filled it with more potion.”
“And then the Dark Lord sailed away, leaving Kreacher on the island…”
Harry could see it happening. He watched Voldemort’s white, snakelike face vanishing into darkness, those red eyes fixed pitilessly on the thrashing elf whose death would occur within minutes, whenever he succumbed to the desperate thirst that the burning poison caused its victim… But here, Harry’s imagination could go no further, for he could not see how Kreacher had escaped.
“Kreacher needed water, he crawled to the island’s edge and he drank from the black lake… and hands, dead hands, came out of the water and dragged Kreacher under the surface…”
“How did you get away?” Harry asked, and he was not surprised to hear himself whispering.
Kreacher raised his ugly head and looked Harry with his great, bloodshot eyes.
“Master Regulus told Kreacher to come back,” he said.