Save the What? When?

I have been reading a book on screenwriting called Save the Cat! I love cats, but I wondered what a book about screenwriting had to do with felines. Blake Snyder, the author of this book with the orange tiger kitty swinging across the front, explains that the "save the cat" scene in a movie is when the audience observes the hero doing something that makes him likable--such as saving a cat. This action defines the character as a good guy. Score.

I got the impression that this saving business should happen sooner rather than later, as in when the audience first meets the main character, at least in a movie. But is this necessary in a novel?

I can't help thinking about one of my favorite classics—A Christmas Carol by Charles Dickens. In this fabulous tale of redemption, Ebenezer Scrooge is far from saving any cats when the reader meets him. Yet, at least for me, Scrooge is still a compelling character. Yes, he's cynical (you know: "bah humbug"), but he is also lonely and empty.

It seems to me that Charles Dickens sets Scrooge up to be such a crusty dude that the reader senses that change must come. The story becomes more interesting because the reader wants to understand why Ebenezer has developed into such a callous of a human being.

So, by the time ol' Ebenezer finally has an epiphany, at the end of the story, and saves a cat, the reader practically cheers (or, at least, this reader did). The reader has been hoping that the wicked can turn kind-hearted, and Scrooge has. By the close of the story, he has saved multiple cats and this works.

What do you think? In a novel, does a character need to save a cat right away? Is Charles Dickens the only guy who can pull of making a main character pretty unlikeable and yet compelling until the very end of a story?