Mystrade with troubled teenage twins

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So the fic that I'm searching for I read on AO3. It's an established Mystrade and in the first chapter Greg is home when there's a knock at the door and there are these two kids,a boy and a girl teenagers twins, and they are there to return Greg's suitcase. The girl sort of freaks out when they discover that Greg is a DI but the boy is ok with it. Mycroft gets home and I think Greg invites them to have dinner and they end up staying the night. Greg gets attached and so does Mycroft, they sort of keep an eye on the kids. The kids father is a drug leader who hits them and forces them to sell drugs. The girl always tries to defend her brother from their abusive father. At one point they run away after the father hits them and the girl defending her brother hits him with something and kills him. Greg and Mycroft send Sherlock and John to find them. I remember that they go to the kids school and Mycroft says that the boy had some disorder that Sherlock had. I remember more of the fic but have research on AO3 and google for the past 3 months or so and haven't been able to find anything, I'm hoping that someone in this community recognizes the fic. I do remember more of the fic but I don't want to give all the plot away, but if someone needs more detail to jog their memory I'm will to give it.

Thank you!!