The forgotten daughter

What if Lily and James Potter had a daughter, their first born, Darcy Potter. They abandoned her when she was only 1, while Lily was pregnant with Harry. They abandoned her because she was a squib, and they didn't want a weak person in their family.
Now she's working in the NYPD, and is the best detective in the Nine - Nine and is engaged to Jake Peralta.
What happens when the Nine Nine and Hogwarts watch Darcy's life.
Chaos happens.