I do not remember where I read it since I was on my phone and thought I saved it but I can't seem to find it. I feel like it was located on AO3 compared to fanfiction.net.
The fanfic is about Harry finding out that he is not Lily or James's kid through a letter that tells him to find his uncle by going to this store and say he is looking for something to do with Prince. Turns out he is Severus's nephew that went missing.
I remember a part of the story where Harry is running in from the garden, sad and hurt since he tripped and fell onto his mother's favorite flower. Before he realizes that his mom is standing in front of him. Also that his mom is Male to Female transgender. I think he also arranges to marry Draco. There is also Weasley (except for the twins and some of the older brothers I think) and Herminone bashing too.