Prisoner of Sin(FMA fanfic)

~~"You let that little brat escape?"envy yells at lust. Lust shrugs "You'll have to find her, gluttony will just eat her and she'll recognize me." she says smiling. I sigh annoyed, turning to leave. As i look outside at the rain i wonder 'why me?'~~
A nameless girl appears on the steps of HQ in the middle of a rain storm. She has scars running up her arms and is nervous around everyone. This little girl seems to know somthing about the homunculi, but in the meantime it seems they're out looking for her. What does this little girl have to do with them and who is she.