You are an orphan girl/boy living in a orphanage since your a kid,your parents have abandoned you. You never saw the outside world until one day a couple decided to adopt.After signing,you were now a part of their family. Now you and they were in living with your things for introduce you to their two son Sae and Rin. The boys were silently observing with their sharp and cold, analyzing you before speaking.

Sae : So it's our..sister now? Rin : ....I guess yes