The story is entitled: Truth Beyond Memory It's rated R.
Summary: Minerva McGonagall has a good life: a job she loves, dear friends, a comfortable home, and a relatively new, no strings attached, passionate sexual relationship with the much younger Severus Snape. Indeed, life couldn't be better, until her past comes back to haunt her and threatens to take it all away.
The livejournal version will be an illustrated version.
Thank you. :)