The "sister" part and getting big comes later, but Big Sister is what I'll call her.
About six months after our beloved Brother Kitty went over the Rainbow Bridge to join Sister Kitty, we were out running errands one day and were not far from the regional animal shelter. On an impulse, we decided to go to the animal shelter and look at the kitties they had there. We went into the main room (the very young kittens are in a separate room), and immediately, from under a sort of quilted tube toy/bed, out popped a youngish kitty who meowed at us and rubbed against our legs. We took her over to a bench and put her on our laps. She started purring and walked from lap to lap, rubbing against us. She certainly seemed to have chosen us as her humans, so after a little while, we went out to arrange the adoption. The following day she had her little operation at the shelter, and the day after that, we brought her home. As soon as we opened the door of the carrier, she bounded out and started happily exploring her new home. She wasn't afraid at all. She even used the litter box about five minutes after getting home. She was obviously glad to be home with us, and we were glad to have our new kitty. She was running around excitedly so much, that we called the shelter, because they had told us not to get her too excited because of her stitches. They told us if she was doing it on her own, there wasn't really anything we could do, and not to do anything to get her even more excited. She eventually did settle down, sort of.
All of the photos were taken the first two days she was home. They show a problem that she had for the first three years, a chronic eye infection (we got some medication from the shelter). Fortunately, the eye infection has not recurred for over three years now (knock on wood). When we got the medication, the vet tech let it slip (intentionally?) that Big Sister's allowed time at the shelter was almost up! Big Sister is a wonderful kitty and we love her dearly.