Disclaimer: Text in italics is taken from HP & The Deathly Hallows and is property of JK Rowling. I am merely borrowing it as a reference.
"I have thought long and hard, Severus... Do you know why I have called you back from the battle?"
And for a moment Harry saw Snape's profile: His eyes were fixed upon the coiling snake in its enchanted cage.
"No, my Lord, but I beg you will let me return. Let me find Potter."
"You sound like Lucius. Neither of you understands Potter as I do. He does not need finding. Potter will come to me. I know his weakness, you see, his one great flaw. He will hate watching the others struck down around him, knowing that it is for him that it happens. He will want to stop it at any cost. He will come."
"But my Lord, he might be killed accidentally by one other than yourself —"
"My instructions to my Death Eaters have been perfectly clear. Capture Potter. Kill his friends — the more, the better — but do not kill him.
"But it is of you that I wished to speak, Severus, not Harry Potter. You have been very valuable to me. Very valuable."
"My Lord knows I seek only to serve him. But — let me go and find the boy, my Lord. Let me bring him to you. I know I can —"
"I have told you – " said Voldemort, and Harry caught the glint of red in his eyes as he turned again, and the swishing of his cloak was like the slithering of a snake, and he felt Voldemort's impatience in his burning scar.
But suddenly Voldemort's face split in a gruesome smile and Harry felt a different feeling emanating from him, something that resembled... sick amusement.
"Alright, Severus," said Voldemort in a soft cold voice. "You have proven yourself as my most faithful servant, thus I shall grant you this honour. Go and seek the boy. You have one hour. Then come to me, with or without him."
Voldemort swept from the room without a backward glance and the great serpent floated after him in its huge protective sphere.
Harry heard the man who stayed behind heave a sigh of relief, and found it strange, but before he could put any more thought into it he heard a faint pop and Snape Disapparated, looking for him to bring him to his master.
"What do we do now?" Ron whispered from behind him.
"I don't know..." Harry whispered back, despair slowly creeping upon him. He had a nasty feeling that everything they did would be in vain.
"Try to find out where he went again," Hermione suggested.
Before Harry could close his eyes to dive into Voldemort's mind once more, a high, cold voice spoke so close to them that he almost jumped to his feet and bumped his head against the ceiling of the narrow tunnel, thinking that Voldemort had found their hiding place.
Voldemort's voice reverberated from the walls and floor, and Harry realized that he was talking to Hogwarts and to all the surrounding area, that the residents of Hogsmeade and all those still fighting in the castle would hear him as clearly as if he stood beside them, his breath on the back of their necks, a deathblow away.
"You have fought," said the high, cold voice, "valiantly. Lord Voldemort knows how to value bravery.
"Yet you have sustained heavy losses. If you continue to resist me, you will all die, one by one. I do not wish this to happen. Every drop of magical blood spilled is a loss and a waste.
"Lord Voldemort is merciful. I command my forces to retreat immediately.
"You have one hour. Dispose of your dead with dignity. Treat your injured.
"I speak now, Harry Potter, directly to you. You have permitted your friends to die for you rather than face me yourself. I shall wait for one hour in the Forbidden Forest. If, at the end of that hour, you have not come to me, have not given yourself up, then battle recommences. This time, I shall enter the fray myself, Harry Potter, and I shall find you, and I shall punish every last man, woman, and child who has tried to conceal you from me. One hour."
Both Ron and Hermione shook their heads frantically, looking at Harry.
"Don't listen to him," said Ron.
"It'll be all right," said Hermione wildly. "Let's — let's get back to the castle, if he's gone to the forest we'll need to think of a new plan —"
They crawled back through the tunnel, none of them talking, and Harry wondered whether Ron and Hermione could still hear Voldemort ringing in their heads, as he could.
You have permitted your friends to die for you rather than face me yourself. I shall wait for one hour in the Forbidden Forest... One hour...
"Harry, put your cloak back on," Hermione whispered when they emerged at the Whomping Willow. "You need to be careful. Snape is looking for you."
He did as he was told and slowly they trudged back to the front door, Ron and Hermione looking nervously around them in case Snape emerged out of nowhere and demanded to reveal Harry's whereabouts.
He turned away and ran up the marble staircase. Lupin, Tonks . . . He yearned not to feel. . . . He wished he could rip out his heart, his innards, everything that was screaming inside him. . . . The castle was completely empty; even the ghosts seemed to have joined the mass mourning in the Great Hall.
Harry ran without stopping, his cloak of invisibility slipping off his shoulders carelessly, and he did not slow down until he reached the stone gargoyle guarding the Headmaster's office.
"Password?" the gargoyle asked Harry's head floating in front of it, the rest of the body hidden under the cloak.
"Dumbledore!" said Harry without thinking, because it was he whom he yearned to see, and to his surprise the gargoyle slid aside, revealing the spiral staircase behind.
But when Harry burst into the circular office a dazzling jet of bright red light hit him, knocking him backwards, and his wand flew out of his hands into the hands of a man he hated perhaps even more than he hated Voldemort himself.