"Harry, after he was attacked by Nagini, you went up to him. You swore you hated him, that you would have killed him given the chance. So why did you go up to be with him as he died...?"
At Minerva's insistence, Harry and Al visit the Head's Office.
Trelawney spills some information the night Dumbledore is killed, and Harry forces Snape to spill his greatest secret.
"Wormwood and asphodel were the first potions ingredients Professor Snape ever taught me about. The very first things he spoke to me about, in fact. Up until now, that was a hard memory to recall."