Aftermath
There was not a single glass object within his reach that wasn't broken. The whole downstairs of his house had felt his rage. Even the precious books that he had scrimped and saved to buy were not exempt from his sorrowful wrath. "YOU PROMISED ME DUMBLEDORE! YOU PROMISED THAT SHE WOULD BE SAFE! I SWEAR BY ALL THE GODS THAT I WILL KILL YOU FOR THIS!" And suddenly, the room was empty. Severus reappeared outside the gates of Hogwarts and made his way up to the castle. His entire body was vibrating with the rage and anguish that he felt and he swore that, before he left, Dumbledore would feel some of the agony that he was in. And then, all of a sudden, he was before the entrance to Dumbeldore's office, and perhaps the old man really was omniscient for the gargoyles sprang apart without him having to utter a word. Or perhaps he had the good sense to tell them to let me in when I arrived, thought Severus as he climbed the winding stairs. It would not have gone well for them if I had had to force my way in. And there he was, sitting calmly behind his desk as if nothing had happened that night. Only his eyes belied the sorrow that he too must have been feeling. "Sit down Severus, please." The use of the word 'please' caught Severus' attention, and the anger that had brought Severus to Hogwarts abruptly drained out of him. "I thought…you were going…to keep her…safe…" They spoke for what felt like hours, or Dumbledore spoke and Severus listened. Dumbledore wasn't convinced that the Dark Lord was gone forever, a wizard that powerful was sure to leave some remnant of himself behind and when it reappeared they must be prepared. "Don't you see Severus, you must protect Harry Potter! The pro-" Dumbeldore cut himself off before he could continue, and Severus raised his head and looked at Dumbledore squarely in the eyes. "What I must do is this Dumbledore: I will protect the boy, for Lily. But do not think that I have forgotten your failure tonight. Whatever you may say it was your fault that she died. I don't know what you could have done to save her, but I do know that when He breached the barriers protecting the house, YOU should have been there to stop him. And you weren't. No one will ever know that truth as I know it, and know this Dumbledore, I will kill you one day for allowing her to die. For not deeming her life important enough to save, you will die." Dumbledore looked stricken at Severus' words, as if he had not imagined that what had happened that night was in any way his fault. "Severus…" But Severus had already gotten up to leave. He was uninterested in hearing whatever platitudes Dumbledore would attempt to press upon him. "I gave you my word Dumbledore and I will not break it. As long as you believe that our world is endangered by Voldemort I will act as your man. But the instant that you believe our world is safe is the moment in which you die."