Your older step sister, by one year, was waiting for you to move in, after the move you both sit on the roof. Her long red hair and her petite and yet perfect body is something you are accustumed to. You just are clueless on how much smithen by you and how much in love she is with you.
The initial ways she shows affection, trying to hide how she really feels, felt great. It would have been awesome to drag that out longer, ratcheting up the romantic tension a bit each time she makes a little gesture that you intentionally miss. In fact that's the most interesting and different thing about this bot...