Severus watched as the angry limping man approached the hospital door. He knew he had to open it, that was his job, especially for anybody with a disability, but he always liked to wait until the last moment, let them reach out to open it themselves and then beat them to it. This job afforded very few pleasures. But as the gust of winter wind hit him, the searing pain in his neck made him let go.
"What's wrong with you?" demanded the man whose face he'd just smashed with the door.
"Nothing." Snape managed to say, still gritting his teeth against the pain.
"Let me see your neck." the man insisted, trying to pry away Snape's hand.
Snape managed to pull himself together, smoothing his face into a picture of ease."There is nothing wrong with my neck, doctor. I apologize for letting the door slip."
House eyed him suspiciously for a few seconds and then walked away without another word. Snape resisted the urge to swear, he knew he was in trouble. He had intrigued Gregory House.
Back in his squalid apartment, Snape sat on the threadbare sofa, thinking furiously. His finger absentmindedly stroked the spot under his collar where nearly thirteen years ago Nagini had punctured his throat. He could not understand why this was happening. Never, in all the time since he had left the wizarding world had his scars hurt so intensely. Granted, it did often get worse with the cold, but it had never been so bad to cause him to let his guard down. And what a mistake that had been. He could still see it, that burning look of curiosity on House's face. Stupid stupid stupid. He should never had allowed that moment of weakness. It was going to be very difficult to shake him now - the entire hospital knew House's reputation, once he finds himself a mystery, he doesn't stop until he's solved it. He even drugged a reluctant patient once, Snape remembered suddenly and resolved to put as much distance between himself and the doctor as he could. The last thing he needed was a nosey muggle finding out about the pain. Not that he could ever find a reason, even Severus himself couldn't. He shut the heavy book in his lap in frustration. There was nothing in there, he had already read it a dozen times. He really was kidding himself about finding any answers in a book, he knew that even in his great collection there was nothing useful. There was simply no precedent for the things Voldemort had done. Nobody else had been stupid enough to make a horcrux out of a living animal, and nobody but Severus had ever survived being bitten. He shouldn't have survived either.
A shiver ran down his spine as he remembered the events of that horrible night. He knew he was dead the moment Lucius has summoned him, and he had panicked because Potter was nowhere to be found, but not daring to keep the Dark Lord waiting, he went immediately hoping he would run into him along the way. He had expected the killing curse: quick, painless, an easy way to go. But the Dark Lord had never been one to make things easy for Severus. After the snake bit there was nothing but pain. White hot pain surging through his entire body, as he struggled to regain control of himself. He had to find Potter. And then, in perhaps the only strike of luck Snape had ever had, Potter came into the shrieking shack. Having given him his memories, Snape was finally ready to die. But he didn't.
He lay there, unable to move, to speak, feeling his blood slowly trickle down the wounds in his neck, the pain from the venom never subsiding. He felt it when the Dark Lord died. He couldn't explain it, he simply knew. After several agonizing hours, he heard voices and footsteps approaching the shack. It was Minerva, with Granger and Longbottom. They had come to collect his corpse. But as they hauled him onto the stretcher, Granger gave a little shriek, "I.. I think he's alive. He has a pulse." Minerva rushed him to the hospital wing.
For weeks he stayed in that same condition, not dead but not quite alive either. Still paralysed, his mind alternating between horrific nightmares and brief moments of lucidity when he could remember where he was and why. He still couldn't decide which was worst. Poppy fretted over him, not knowing what to do. Aside from casting a spell on his eyelids so he could blink when he was awake and another one to inject nutrients directly into his bloodstream, all she could do without fear of worsening his condition was wait. Eventually the pain began to fade a little and he slowly regained control over his body. It was several months before he could walk again and even more before he could speak. Minerva would come to visit him sometimes, telling him about the reconstruction of Hogwarts, the new Ministry, the dead, the living, the plans to reopen the school the next year. Occasionally, the Lovegood girl would visit him too but she never said anything, she just sat there staring at him or reading the Quibbler for what felt like an eternity. He supposed she was trying to be kind, to keep him company - although why he could never understand - but it made him extremely uncomfortable.
And then came the trails. Although apparently Potter had been advocating for him, most of wizarding Britain still believed he was a death eater. They were not satisfied until they had all seen the memories themselves. It was bad enough to have to face Potter after what he now knew about him, having to rely on him to stay out of Azkaban, but having his most private feelings displayed to the entire country, described in a disgustingly exaggerated article in the Daily Prophet, having strangers give him looks of pity or admiration and whisper things among themselves as he passed by was absolutely intolerable.
He turned down Minerva's offer to return to teach at Hogwarts, sold the Spinner's End house he despised and bought the first plane ticket out of there. He did everything the muggle way because he had no desire of alerting the local wizarding authorities of his presence, the last thing he needed was to make himself noticeable at the place he had come to escape. So ended up in America; it was convenient because they had made a point about not getting involved in the war against Voldemort, so it was very unlike that anyone would know who he was. Also, there wasn't much of a magical population in New Jersey.
Minerva had stopped owling him after about a year of getting no responses. For all intents and purposes he no longer existed to the wizarding world and he liked it that way. With no master left to serve, no war to fight, nothing, in short, left of what had defined him, he was lost. He lived only because he couldn't muster the will to kill himself. He had been comfortable in his numbed misery for years, but now the increasing pain in his neck was making him uneasy, forcing him to think again about everything he had tried so hard to forget.