Ten years after the battle of Hogwarts is won, Horace Slughorn finally retires and Harriet Potter accepts the vacant position of potions Master at Hogwarts. Only days into her first week, things start getting strange. Objects are moved around in her office and living quarters, she wakes startled in the night to phantom voices and the feeling of someone watching her.
The occurrences continue to happen with regularity for her entire first year. The first night of her second year teaching though, she wakes up laying next to someone who was supposed to be dead. The one person she never got the chance to thank, the man who protected her all throughout her years at Hogwarts, the man who died in her arms. Severus Snape. Only, he's not a ghost, or at least she doesn't think so, because she can touch him, also, why the hell does he look so young?
...
Time anomaly, Harriet has the same office and living quarters that were once Snape's, and the two of them are accidentally haunting one another, Snape from the 1990 - 1991, Harriet from 2010 - 2011.
Snape thinks he's dreaming, or maybe hallucinating when he first sees the woman in his private quarters, seated on his arm chair, reading a book he's never even heard of authored by Silvanus Prince, his secret nomme de plume. When he tries to get a closer look, the woman vanishes. After that though, he sees her at least once a day, in his office, in his quarters, and occasionally even in his bed. He has tried speaking with her multiple times, but she never answers, merely looks around suspiciously, before going back to what ever she has been doing before. Any time he tries to touch her, she fades away like mist. After some time, he starts speaking to her as if she were actually there, holding one sided conversations, he starts getting up early in the mornings because he noticed her habit of sitting in the breakfast nook and having a cup of tea in the mornings between 5 and 6am. He also switches his side of the bed, because she sleeps on the one he normally does. For an entire year, she becomes his near constant companion, someone whom he has spilled his very heart out to, and in fits and turns wishes were real, until the day she becomes so.
It's the first night of the new term of the 1991 school year, and coincidentally the year Potters spawn first started. He was of course sorted Gryffindor, as expected from all the reports Albus had given him over the years, about the mischievous brat who not only looked like his father, but certainly lived up to the man's horrid bullying reputation. Raised like a pampered spoiled prince, wanting for nothing and doted upon by his secret guardians.
He was late back to his quarters that night, having an incident with one of the first years, and all he wanted to do was fall into bed and sleep for the next seven years, until the brat graduated and left his life for good.
There was one bright spot in this wretched day though, his mystery woman was already waiting for him, snuggled half under the covers, with a defence book laying open on her chest, eyes closed as if she had been waiting for him while reading in bed, but fallen asleep. He longed to lay the book on the bedside table, tuck her fully in and hold her close as he drifts off to sleep, but settled for climbing onto his side of the bed, apologizing for keeping her waiting and wishing her goodnight. Only to have her eyes snap open, and for the first time since she began appearing, look directly at him. He stared right back, not wanting to hope that she was indeed looking into his eyes, and not perhaps at something behind him. When he heard her speak for the first time though...
"Am I dead again?"
"What do you mean again?"
Then she pokes him, shrieks and launches herself out of bed, wand drawn and defensive stance ready.
_____
Harriet is stuck in an alternate universe where her counterpart is a boy, her old professors counterpart has some kind of obsession with her, that her fucked up brain is all too ready to reciprocate, also, when the hell did he get so hot? So she does what any totally sane and not reckless and reactionary person would do; she adopts her alternate self, averts a war, and destroys the man who made her life a living hell before sending her off to her death.