Is there a chance? DEFINATELY! they only met three times - thats nothing in cat terms. It took Pouncer 6 months to even tolerate Flutter. Now she's the only one who plays and wrestles with him. Allen took only a week to love Pouncer. What I'm satying is every cat is different as to how quickly they adjust to a new cat in the household but eventually they do come to like each other. Its rare that one cat HAS to be an only cat, so since this si only the 3rd meeting, I'd say give your cat more time to adjust to his new sister.