As we head into the season finale of "Mad Men"'s fourth season (airing Sunday on AMC), this much (or little) we know for sure: Per AMC's website, the episode is entitled "Tomorrowland" and in it, "opportunity arises for Don and Peggy." What do critics and bloggers think will befall the inhabitants of the set-in-1964 "Mad Men" world, last seen contemplating the forced closure of Sterling Cooper Draper Pryce? Here, 6 possibilities:

1. Joan will reveal that she's with child
"We all think that Joan is still pregnant, right?" muses Erika Villalba at Culture Mob. It's unclear whether the agency's bombshell office manager (impregnated by senior partner Roger Sterling) actually went through with the abortion, and given that she was trying to conceive with husband Greg before he left for basic training, she could probably pass off the child as his. "[Greg] might be a doctor, but he’s kind of a shitty one." When interviewed about the possibility of a still-pregnant Joan, creator Matthew Weiner told TV Squad: You're gonna have to watch the episode."

2. Disney saves the business
The episode's title, "Tomorrowland," is the "biggest clue," says Allison Waldman at TV Squad, who theorizes that Walt Disney will come to the agency's rescue as its big-new-client angel. In 1965, Disney "was riding high" with four attractions at the New York World's Fair, including one called "Tomorrowland," and was about to announce plans to build Disney World in Florida. And don't forget that Walt Disney suffered from lung cancer; he might have responded well to Don's recent anti-tobacco screed. Nah, says Michael Agger at Slate. Too "obvious."

3. A tragedy befalls Sally
I can't help but fear for Don's mercilessly traumatized daughter Sally, says Logan Hill in New York. "I'm really afraid that she's going to commit suicide in this finale," adds Michael Ausiello in an Entertainment Weekly roundtable discussion. "All season, I felt like that's where this is leading."

4. Roger Sterling takes his own life
An alternate suicide scenario: "I'm thoroughly convinced" that Roger Sterling's death by suicide is imminent, says The Pre-Existential Suite. "The writers have written him into a casket." Joan's gone, his career's dead; there's nothing left for him to do. "Roger's suicide would bring Don’s general existential angst into proper focus for him and let Don directly confront his fear of his own mortality." John Slattery, who portrays Sterling, laughs off this notion in a recent New York interview: "[Roger] doesn't have the backbone to kill himself."

5. Everything goes dark
Blogger Matt Maui at Basket of Kisses wonders if the series' writers will use the Great Northeast Black-Out of November 1965 as a "device to pay off the various story lines developed this season." In which case, muses Christopher Rosen at Movieline, Don and Peggy could get caught in an elevator and finally "consummate their relationship."

6. Don will lose his knack of breezily turning tragedy into triumph
Last season ended with Don's uplifting scheme to save his company, says Sady Doyle at The Atlantic. But now "the character appears to have reached the point of no return; we've seen the man commit so many acts of thoughtless cruelty, and wreck his own chances at happiness so many times" that the equation has become more complex. "Either Don will score a hollow victory, or the show will crush us with his entirely realistic defeat." Creator Weiner, in an otherwise revelatory interview with TV Squad, is giving little away: "Don is confronting himself, Don is losing all these things, Don doesn't know who he is." We've been "seeing him pushed to the end, and seeing him either rise to the occasion or... not."