Almost against his will he glanced from Ron to Hermione, both of whom looked devastated.

“I messed up, Harry,” said Ron bleakly. “We did like you told us: We checked the Marauder’s Map and we couldn’t see Malfoy on it, so we thought he must be in the Room of Requirement, so me, Ginny, and Neville went to keep watch on it… but Malfoy got past us.”

“He came out of the room about an hour after we started keeping watch,” said Ginny. “He was on his own, clutching that awful shriveled arm—”

“His Hand of Glory,” said Ron. “Gives light only to the holder, remember?”

“Anyway,” Ginny went on, “he must have been checking whether the coast was clear to let the Death Eaters out, because the moment he saw us he threw something into the air and it all went pitch-black—”

“—Peruvian Instant Darkness Powder,” said Ron bitterly. “Fred and George’s. I’m going to be having a word with them about who they let buy their products.”

“We tried everything, Lumos, Incendio,” said Ginny. “Nothing would penetrate the darkness; all we could do was grope our way out of the corridor again, and meanwhile we could hear people rushing past us. Obviously Malfoy could see because of that hand thing and was guiding them, but we didn’t dare use any curses or anything in case we hit each other, and by the time we’d reached a corridor that was light, they’d gone.”

“Luckily,” said Lupin hoarsely, “Ron, Ginny, and Neville ran into us almost immediately and told us what had happened. We found the Death Eaters minutes later, heading in the direction of the Astronomy Tower. Malfoy obviously hadn’t expected more people to be on the watch; he seemed to have exhausted his supply of Darkness Powder, at any rate. A fight broke out, they scattered and we gave chase. One of them, Gibbon, broke away and headed up the tower stairs—”

“To set off the Mark?” asked Harry.

“He must have done, yes, they must have arranged that before they left the Room of Requirement,” said Lupin. “But I don’t think Gibbon liked the idea of waiting up there alone for Dumbledore, because he came running back downstairs to rejoin the fight and was hit by a Killing Curse that just missed me.”

“So if Ron was watching the Room of Requirement with Ginny and Neville,” said Harry, turning to Hermione, “were you—?”

“Outside Snape’s office, yes,” whispered Hermione, her eyes sparkling with tears, “with Luna. We hung around for ages outside it and nothing happened… We didn’t know what was going on upstairs, Ron had taken the map—It was nearly midnight when Professor Flitwick came sprinting down into the dungeons. He was shouting about Death Eaters in the castle, I don’t think he really registered that Luna and I were there at all, he just burst his way into Snape’s office and we heard him saying that Snape had to go back with him and help and then we heard a loud thump and Snape came hurtling out of his room and he saw us and—and—”

“What?” Harry urged her.

“I was so stupid, Harry!” said Hermione in a high-pitched whisper. “He said Professor Flitwick had collapsed and that we should go and take care of him while he—while he went to help fight the Death Eaters—”

She covered her face in shame and continued to talk into her fingers, so that her voice was muffled. “We went into his office to see if we could help Professor Flitwick and found him unconscious on the floor… and oh, it’s so obvious now, Snape must have Stupefied Flitwick, but we didn’t realize, Harry, we didn’t realize, we just let Snape go!”

“It’s not your fault,” said Lupin firmly. “Hermione, had you not obeyed Snape and got out of the way, he probably would have killed you and Luna.”

“So then he came upstairs,” said Harry, who was watching Snape running up the marble staircase in his mind’s eye, his black robes billowing behind him as ever, pulling his wand from under his cloak as he ascended, “and he found the place where you were all fighting…”

“We were in trouble, we were losing,” said Tonks in a low voice. “Gibbon was down, but the rest of the Death Eaters seemed ready to fight to the death. Neville had been hurt, Bill had been savaged by Greyback… It was all dark… curses flying everywhere… The Malfoy boy had vanished, he must have slipped past, up the stairs… then more of them ran after him, but one of them blocked the stair behind them with some kind of curse… Neville ran at it and got thrown up into the air—”

“None of us could break through,” said Ron, “and that massive Death Eater was still firing off jinxes all over the place, they were bouncing off the walls and barely missing us…”

“And then Snape was there,” said Tonks, “and then he wasn’t—”

“I saw him running toward us, but that huge Death Eater’s jinx just missed me right afterward and I ducked and lost track of things,” said Ginny.

“I saw him run straight through the cursed barrier as though it wasn’t there,” said Lupin. “I tried to follow him, but was thrown back just like Neville…”

“He must have known a spell we didn’t,” whispered McGonagall. “After all—he was the Defense Against the Dark Arts teacher… I just assumed that he was in a hurry to chase after the Death Eaters who’d escaped up to the tower…”

“He was,” said Harry savagely, “but to help them, not to stop them… and I’ll bet you had to have a Dark Mark to get through that barrier—so what happened when he came back down?”

“Well, the big Death Eater had just fired off a hex that caused half the ceiling to fall in, and also broke the curse blocking the stairs,” said Lupin. “We all ran forward—those of us who were still standing anyway—and then Snape and the boy emerged out of the dust—obviously, none of us attacked them—”

“We just let them pass,” said Tonks in a hollow voice. “We thought they were being chased by the Death Eaters—and next thing, the other Death Eaters and Greyback were back and we were fighting again—I thought I heard Snape shout something, but I don’t know what—”

“He shouted, ‘It’s over,’” said Harry. “He’d done what he’d meant to do.”

They all fell silent. Fawkes’s lament was still echoing over the dark grounds outside. As the music reverberated upon the air, unbidden, unwelcome thoughts slunk into Harry’s mind… Had they taken Dumbledore’s body from the foot of the tower yet? What would happen to it next? Where would it rest? He clenched his fists tightly in his pockets. He could feel the small cold lump of the fake Horcrux against the knuckles of his right hand.