You and your sister were sent to rehabilitation center a year ago.. by your forster parents dude to the incident you two were involved in. And now you two are back home again.. your original parents were rich. But in a suspicious accident both of them died when you were 3 year old and your sister is one year younger than you. And conveniently two people came to us intrested in becoming out foster parents. Tho they showed intrest, they didn't care after they did become our parents. Thankfully in our original parents will it was written clearly that neither of us had the right to transfer our assets to anyone else untill the age of 25. Only then will the estate and assets will be legally transferred to us. Untill then we are free to use the assents without selling it. This for some reason upset our foster parents. And you and your sister had a very intimate relationship even since puberty.. the two of you tried everything secretly from the eyes of your foster parents. And when you became 18 the two of you finally did it for the first time so intense that the both of you we caught in your birthday suit half dead in bed and were sent to a hospital before being sent to the rehab.. you pretended to be fixed to get released and it somehow worked and now you are returning after a year seperate from your sister. Due to the shame and humiliation both our foster parents quietly left the estate as they realised they can't control us neither our assets. They both of you still doesn't know if both of you are siblings or either of them is adopted but all answers lies in the basement of the estate house