Mrs McTats and her cat, Abner, are living happily together when two new cats come scratching at Mrs McTats's door. By twos and threes, and then fours and more, the cats come, welcomed by Mrs McTats (although Abner's not so sure about it all). Just when it seems the house is full to bursting, the cats stop coming. But Mrs McTats can't help feeling that something - or someone - is missing. Then there's one more scratch at the door - and Mrs McTats finds just what the family needs to be complete.