May became June, and Dumbledore's year wilted down to a month. He seemed unperturbed by this, and in a true Luna Lovegood-esque fashion, on what was to be his last night alive, he seemed to care more about taking the Horcrux Who Lived on a ridiculous mission to seek and destroy another bit of the Dark Lord's tether to the living world, than about his own demise.
With Albus and Harry gone, the only useful thing left to do was to look out for Draco - but he was nowhere to be found.
In a panic disguised as a plain foul mood, Severus paced around the castle, snarling and barking at everyone who crossed him, and when that (to the surprise of no one) proved futile, he returned to his office to pace there.
Then his left arm began to burn. The despised mark was darker than usual, and yet it seemed to glow. He walked out, of course, two members of Dumbledore's so-called army were standing outside his office as if they had nothing better to do with their young lives than to cross paths with a death eater when Dumbledore is away.
He warned them of trouble in the seventh floor and hurried to the Astronomy Tower. The Dark Mark shone high above it, and the stone itself shone a sickening green.
He clutched his wand - the real wand - it was burning his hand with urgency.
He climbed the stairs. He could not hear himself think, even though it was disturbingly quiet. He climbed some more stairs, and then some more ( Rowena Ravenclaw, why did you have to design such an infernal castle?! ), and then some more. Then, there were no more stairs, no way to go but forward, and time stood still for one blessed moment before he opened the door.
He surveyed the room. Death eaters. Draco. Dumbledore. Everyone were alive, still.
A second of eye contact with Draco was enough. He was too overcome to occlude anything at all. He told Severus everything without feeling or knowing he was doing it, through his very own blue eyes:
Draco Malfoy managed to get death eaters into the most magically fortified castle in the world. He had the "great" Dumbledore as good as dead, wandless, powerless . But he could not kill. He could not reap what he worked so hard to sow. And Dumbledore had the gall to offer him protection. Dumbledore was the one who needed protection from Draco!
And yet, Draco could not kill, could not complete the task, just when he was so close, he let Dumbledore get in his head, he let him talk himself into chaos and confusion. When Snape and the death eaters came, Draco felt relief intermingled with shame - he failed, but help was here.
Having spent so much time practicing legilimency and occlumency with the Headmaster, a passing glance was enough for Severus to get all the information he needed about what just transpired. Harry is here, under the cloak. Petrified. I offered Draco Protection. Good luck . He didn't need more than the telegraphic message to know what Dumbledore was thinking. He knew Draco was not going to accept the offer; he also knew offering refuge and protection planted a seed that will grow into understanding, one day, that the Dark Lord cared for no one, that everyone were disposable to him, not least Draco himself, whereas Dumbledore was willing to help and protect him and his family unconditionally. By offering forgiveness even as he was being assaulted, the greatest wizard in the world was performing magic that was truly great, despite hardly being magic at all.
Severus had to admit it, just as he was about to end the man's life life - Dumbledore made great mistakes, but he was a great wizard and a great man.
Dumbledore pleaded: "Severus, please…" Severus towered over him, his left arm burning, his wand hand clutching so tight that he thought the wand might break. He looked at Dumbledore.
Why did you have to make it so hard at the last moment? Do you truly want me to do it? I can't do it. I can't.
He was certain that Potter must view him as the utmost traitor, the ultimate coward, pointing his wand like that at a defenseless man.
Terrible images from Dumbledore's mind flashed before Severus, as if they were his own fears. Voldemort was using Dumbledore as an Inferius, forcing his mutilated corpse to do his bidding… He was alive, but the curse weakened him, and Bellatrix was torturing what was left of him... Draco was being punished for his failure and Snape was not there to protect him, because neither of them killed Dumbledore. I get it. I will miss you, Albus. Thank you for everything. Thank you for Figg .
He imagined the great wizard as an Inferius as he cast a perfect Killing Curse.
Albus Dumbledore's body was blasted off from the roof of the tower down to the ground.
Now, a thousand thoughts rushed through him at once.
By killing him on school grounds, he could at least make sure the body was safe. By using the Killing Curse, he knew there was no suffering. He also knew Voldemort's ideas about the internal mindset required to cast it truly rendered him above suspicion.
But Dumbledore was now gone, and with him, whatever faith the members of the Order and the staff had in him.
And of course, on top of it all, there was the issue of Harry Potter. Realizing that he was petrified by horror and not by magic, Harry Potter rushed heroically to make sure Dumbledore and Lily's deaths will be in vain. The boy for whom two great souls and however many not so great souls had died could not wait to follow in their footsteps.
They were on the ground, near Hagrid's hut. He grabbed Draco by the scruff of his neck and cast the shocked boy aside.
Fortunately, he was still unable to close his mind. He was so overcome with raw emotions, base, unsophisticated emotions, that Snape could neutralize him with almost no effort.
It was, in fact, so easy, that he had plenty of time to think. This is the chosen one? This is the boy who is destined to defeat Lord Voldemort? The boy shouting spells at me even as he knows I already know what counters to use by reading his mind? And he is telling me to fight him? He is as arrogant as when he first got here. Oh Trelawney. What have you done.
And then Potter said the words "kill me like you killed him, you coward", he said them without thinking them first, and it pierced his heart, hit him harder than any spell in Potter's limited vocabulary.
"DON'T!", Severus shouted. He contorted his face, for behind his eyes he was burning, and he was sure he will collapse in tears. If the boy could practice legilimency, he would have seen it all…. I did not mean to kill him, I did not mean to kill your father, he died for her, and I did not want to kill Albus… You must die, Harry - but not now. Only when the time is right . But Harry Potter could not practice legilimency, and so he saw nothing. There was only one way to finish the sentence that was not ridiculous: "CALL ME A COWARD!", he bellowed like a beast, wishing he could say what he meant: "DON'T DIE FOR THE OLD FOOL".
The death eaters came, and they cruciated Harry, closing in on him, about to capture him. Severus shook the sudden fit of nostalgia. He reminded the death eaters that Potter belongs to the Dark Lord, thought to himself, Forgive me yet, Lily?, and escaped with the young Malfoy.