Once Upon a Time has thrown out the rulebook, so to speak, in favor of a new one.

On the fantasy drama's two-hour season finale on Sunday (8/7c, ABC), we will see the results of The Author's (Patrick Fischler) new book, Heroes and Villains, in which the good characters we know and love have swapped places with the evil ones that we love to hate. What does this mean besides really awesome costuming? Read on for our best guesses for the finale based on what the producers say, this sneak peek, preview photos and maybe just a little wishful thinking.

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1. The Outlaw Queen could be real It's not just a 'shipping name anymore! In a sneak peek, we see that Regina (Lana Parrilla) has taken the role that Snow (Ginnifer Goodwin) had in the enchanted forest: the fur-wearing scofflaw with royal roots. Could Robin Hood (Sean Maguire) be far behind? It's not entirely clear, but these outfits look like a matched pair, even if he has a Nottingham vibe:

"In the finale we will absolutely get more Robin Hood and Regina and where they stand," co-creator Edward Kitsis tells TVGuide.com.

2. Alas, no literal Captain Swan We were really hoping that in this Heroes and Villains reality, we'd get to see Emma (Jennifer Morrison) take the place of former bad guy Captain Hook (Colin O'Donoghue) in a big, sweeping black duster and possibly darker 'do. And although it seems like she has some swashbuckling skills below, she still has both of her hands:

3. The Author may have lived in the 1960s Is it the real 1960s or a fictional one as in Mad Men? Who knows? The show has played fast and loose with time, especially once we discovered that The Author Isaac loves to visit time periods through books, such as when he helped Cruella (Victoria Smurfit) paint the town red — with blood — in the fictional Jazz Age. He told her, "We're not in a time. We're in a realm of story. There are many. Some beautiful, some horrific, and some just plain magical."

As these photos reveal, it looks like Isaac was some sort of appliance salesman for a store that carries color TVs, which became more popular with consumers in the 1960s. The couple's clothes also point to that decade. Bonus: A shout-out to ABC!

Then again, if Isaac lived during the real 1960s, any sorts of magical reasons could explain why he hasn't aged. Kitsis says, "In the finale, we're also going to learn more about the Author's past. Yes, [through] flashbacks." Also, who's to say that we aren't just all in one big storybook?

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4. Someone's death will set up next year's big plot "We will be telling you what next year is about in the final scene," Kitsis says. "Whereas last year we saw Frozen, and the year before we were going to Neverland, this will be much more like Season 1 in that it's going to be a change in condition." Co-creator Adam Horowitz adds, "There is a death that precedes [the change in condition.]"

5. The Author may die Traditionally, The Author is only supposed to record events, not change them, but Isaac has proven to meddle quite a lot in people's fates, which is why the villains are so riled up with constantly being denied their happy endings. If Isaac makes huge changes to the Storybrooke crowd and then dies, this could set up the change in condition dilemma that's been teased for next year.

"Can the Authorship be passed on? I would say we actually answer that exact question in the finale," Horowitz says. "We show you how Isaac gets to be The Author."

6. Zelena (Rebecca Mader) may die Like The Author, her death could cause problems, especially if she's done something magical or set up a curse that affects everybody. Sadly, it would also eliminate the need to address the fact that she's carrying Robin Hood's baby, which Regina would probably be happy about. Good riddance, half sis!

7. Gold/Rumplestiltskin (Robert Carlyle) may die Hear us out. Although it would be easy for Once to kill off someone that we don't know well or care about (such as The Author or Zelena), wouldn't it matter more if one of the core cast died? Gold's heart has been seriously damaged, and last we saw him, he was drained, sitting on the floor of his pawn shop. Also, Kitsis says that the Belle-Gold-Will love triangle "will absolutely be ending. We'll get a conclusion on that." On one hand, that could mean that Gold's death will remove him from the triangle, but on the other hand, his death could be the catalyst that makes Belle (Emilie de Ravin) realize her feelings for him run much deeper than they do with Will (Michael Socha). What happens if the Dark One dies? We could find out! (Also, rarely does anyone die permanently on this show, so Gold could come back next year.)

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8. Henry may become the next Author We know that Henry (Jared Gilmore) is going to step up his game in the finale. Finally! After all, as the Savior's son and Gold's grandson, we've been waiting for him to get pulled into some sort of grand heroics or show off some innate ability. But why would he become the Author? From the start, he's had an affinity for the original storybook and realized that the stories in it were true. Also, as we've seen this year, he's been central to the success of Operation Mongoose and anything to do with those storybook pages. This might also explain why Evil Snow wants to find him so badly, in order to rewrite the past and bring back her true love. Need more proof that Authorship may be in his future? Check out this photo:

That's a copy of Heroes and Villains, with what appears to be a vintage (1960s, perhaps?) cover. Just as a side note that Isaac's last name on the book is "Heller." Hmm, could this be a hat tip to Joseph Heller, whose novel Catch-22 hit it big around the 1960s?

Also, according to an episode description from ABC, "Henry discovers he has big shoes to fill as he steps up to save his family before the story's final page is turned." What size shoes does Isaac wear? We kid! Sort of.

9. Henry may die As with Gold, having Henry die would make the stakes really matter. If he steps up as Savior Jr., he could make the ultimate sacrifice, and this could cause ripples if he's also the new Author. And it will add some urgency going into the next season if everyone is working to undo this tragedy. Granted, this is probably the craziest theory of all, but would be very interesting to see how Once deals with it.

What are your best guesses for the finale?

Once Upon a Time's two-hour finale airs Sunday at 8/7c on ABC.

Watch a promo for the finale below: