It's driving me mad

So I'm trying to find an AU Harry Potter fic I read, but I might be wrong. I'm going to describe it under a cut because this is public, not everyone has finished the books, and it involves spoilers of the massive kind. And for the record, this was one of those AU fics that actually works. It worked for me, at least.The fic involved Sirius and a change in the fifth book - that's all I'm saying outside of the cut.

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