Author's notes: This was written for the Fandomcommerce exchange on LJ. the prompt I chose was 'Capgras Disorder'. Snape/Hermione was not one of the requester's pairings, but Snape was one of the requested characters, so I made it pretty much Gen. In case you can't tell, this consists of 10x100-word sections. Just because it was easier to write that way. :-) Beta credit to Diamond Dub.
The Perfect Stranger
1. He doesn't know who she is. There is something familiar about her, especially the way she makes things more complicated than they should be, and her exaggerated patience, which is really a disguised impatience. Her hands also create a fleeting association in his head, but he can't figure out what. It's her face that is completely strange and unrecognizable to him. The unremarkable brown eyes over a sprinkling of freckles; the curlicues of wiry brown hair decorating the edges of her face, where they've escaped from her strict, no-nonsense bun. All of this draws a frustrating blank in his mind.
2. She says her name is Hermione Granger. That's a lie, of course. Hermione Granger was Potter's swotty little pal, all big teeth (he remembers taunting her over them himself) and big hair (he remembers the other children laughing over it). He knows what she looked like. She was ... She had ... He pounds his forehead with his fist in frustration. It's been too long. He can't remember all of them anyway, he comforts himself. Sixteen years times forty new students a year, give or take. There's nothing wrong with his brain. This woman is not Hermione Granger, that's all.
3. He wonders why she is posing as Hermione Granger. Why she comes to visit him and fuss over him. Why she doesn't want to give him her real name. She reminds him of Molly Weasley in many ways, but she can't be Molly, because Molly came with her at the beginning. She must have known him Before. That would explain the tendrils of familiarity that nag at him in her presence. Maybe she was one of the poor victims at a Death Eater initiation. If so, it may be a kindness that she hasn't told him who she really is.
4. She used to try and convince him of her identity. She told him things that, supposedly, only Hermione Granger would know. That her mother had had three miscarriages before she was born. That she'd been the one to develop the DA coins, based on a modified Protean charm. It could be true. He wouldn't know. She'd even gone so far as to cast her Patronus for him. The silver otter seemed obscenely frivolous cavorting on his threadbare Chesterfield. He'd never seen Hermione Granger's Patronus before. If this was it, she could do with a new one. He doesn't try his.
5. He has considered that she might be using Polyjuice Potion. He followed her around once, dogging her heels on one of her Saturday visits, to see if she was sneaking a sip. When he asked her if she knew of any innovations to the Polyjuice formula that would allow it to work for longer than sixty minutes, she gave him an odd look, but said she didn't. Of course, she wouldn't give it away if she did. If she really is Granger, why would she use Polyjuice? Might she have been horribly disfigured, like Longbottom or the eldest Weasley son?
6. Her eyes are always drawn to the scars on his neck. She tries not to stare, but he catches her looking whenever she thinks he isn't paying attention. He could cover them up, but that would be drawing even more attention to them, to his mind. It's not like he ever goes out in public anyway, and there are no mirrors in the house. He likes being reminded of them, though. Her looks of pity and revulsion are fuel for his smoldering rancor against the world at large. He needs that. He has nothing else.
7. He lets her shave him because when his neck and chin are smooth, his fingers are less likely to find their way there and be startled by the thick ridges and knots in the skin. The blade is charmed never to cut through dermis, so he isn't worried that she can slice his jugular. He's considered that she's been planted here by one side or the other in order to mete out the justice that was never done. Her hands sometimes shake when she presses the warm metal against his neck. He likes to think she is afraid of him.
8. He knows she pities him, whoever she is. He resents her for that, but he doesn't stop letting her in. At first, it was only twice a week. Now she comes nearly every day, in the evenings, after work. She doesn't try and convince him of her identity anymore. Just smiles tiredly and sends a Dusting Charm swirling around his books and asks if he's had dinner. He used to make a point of taking meals when she wasn't there, hunched over his plate and eating hurriedly. Now he waits for her. She seems to need someone to talk at.
9. One time, he caught her crying in his kitchen. He didn't ask why and she didn't tell him. She didn't come for over two weeks after that. He let his beard grow until he couldn't stand it anymore and cut it crudely off himself. He cursed her for making him become dependent on her. He cursed her for remaining a cipher to him. He nearly went crazy trying to remember what she looked like, even going so far as to attempt a sloppy sketch on a scrap of parchment. He burned it afterwards. It wasn't the face of his stranger.
10. When she came back, she looked both older and younger. She took a deep breath and told him that what was past was past. She was starting a new life. Not that it concerned him. But she would like to continue visiting him, if he didn't mind. He didn't like the way his heart skipped a beat, but he let her in anyway. He closed the door, and it was just the two of them in his shabby little house. Then she laid her hand gently against his cheek and told him he looked like he could use a shave.