It was Addison centric, and was something along the lines of Addison a kid but for some reason, giving the baby to her sister to raise and pretending the baby was her niece instead. Anyway, the niece finds out and comes to Seattle to live with Addison. There was one chapter I remember in which Addison, the niece, Meredith and Izzie went "Black Friday" shopping the day after Thanksgiving.
I have tried every possible way I know how to try and find this fanfic, but it's been killing me for almost a year!
Please help me if you know!
I'm really desperate (hence why I'm posting this because trust me, I know how annoying they are!)
Thank you so much in advance! :)