Rage and resentment fought shock and excitement: for several moments, Harry could not speak.
“It is natural to be afraid,” said Dumbledore.
“I’m not scared!” said Harry at once, and it was perfectly true; fear was one emotion he was not feeling at all. “Which Horcrux is it? Where is it?”
“I am not sure which it is—though I think we can rule out the snake—but I believe it to be hidden in a cave on the coast many miles from here, a cave I have been trying to locate for a very long time: the cave in which Tom Riddle once terrorised two children from his orphanage on their annual trip; you remember?”
“Yes,” said Harry. “How is it protected?”
“I do not know; I have suspicions that may be entirely wrong.” Dumbledore hesitated, then said, “Harry, I promised you that you could come with me, and I stand by that promise, but it would be very wrong of me not to warn you that this will be exceedingly dangerous.”
“I’m coming,” said Harry, almost before Dumbledore had finished speaking. Boiling with anger at Snape, his desire to do something desperate and risky had increased tenfold in the last few minutes. This seemed to show on Harry’s face, for Dumbledore moved away from the window, and looked more closely at Harry, a slight crease between his silver eyebrows.
“What has happened to you?”
“Nothing,” lied Harry promptly.
“What has upset you?”
“I’m not upset.”
“Harry, you were never a good Occlumens—”
The word was the spark that ignited Harry’s fury.
“Snape!” he said, very loudly, and Fawkes gave a soft squawk behind them. “Snape’s what’s happened! He told Voldemort about the prophecy, it was him, he listened outside the door, Trelawney told me!”
Dumbledore’s expression did not change, but Harry thought his face whitened under the bloody tinge cast by the setting sun. For a long moment, Dumbledore said nothing.
“When did you find out about this?” he asked at last.
“Just now!” said Harry, who was refraining from yelling with enormous difficulty. And then, suddenly, he could not stop himself. “AND YOU LET HIM TEACH HERE AND HE TOLD VOLDEMORT TO GO AFTER MY MUM AND DAD!”
Breathing hard as though he were fighting, Harry turned away from Dumbledore, who still had not moved a muscle, and paced up and down the study, rubbing his knuckles in his hand and exercising every last bit of restraint to prevent himself knocking things over. He wanted to rage and storm at Dumbledore, but he also wanted to go with him to try and destroy the Horcrux; he wanted to tell him that he was a foolish old man for trusting Snape, but he was terrified that Dumbledore would not take him along unless he mastered his anger…
“Harry,” said Dumbledore quietly. “Please listen to me.”