How I Met Your Mother

For those who have been waiting six seasons for the answers to some of How I Met Your Mother's biggest mysteries, executive producers Craig Thomas and Carter Bays say Season 7 will offer what you're looking for.

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1. Who's the mother? Just kidding! The producers aren't divulging that detail yet, but "some of the stuff we're doing this season is really digging deep in the How I Met Your Mother mythology," Thomas says.

In fact, Ted's main drive from Day 1 will be the focus of this season, as he tries to figure out why it's taken him so long to actually meet the mother. "Our pilot launched with Ted [Josh Radnor] seeing his two best friends getting engaged and that turned Ted crazy for a night and he told a girl on a first date that he loved her," Thomas says. "Ted has been on all these other journeys, so it's nice to come back and ask the question: What does Ted do now that his two best friends are married and having a kid?

"It's a great recommitting of Ted's journey, where he's like, 'It's time to get serious again!' Ted is going to have a lot of good momentum this year," he continues. "You're going to see Ted be Ted. 'Where's the one? I used to be this guy who had so much heart. I've kind of drifted on that and had some other crazy relationships, what do I do now? How do I get back on that track?'"

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2. When is Lily due? Speaking of Ted's friends, Marshall (Jason Segel) and Lily (Alyson Hannigan) will face the trials and tribulations of pregnancy this season — and they'll be doing it alone. After a false positive pregnancy test, the pair will be more reluctant to jinx the impending baby this time around. "They don't want to do that again and want to wait three months like you're supposed to and not freak everyone out," Thomas says. "But then they go to this wedding and everyone is getting trashed. Lily realizes right when she walks in, 'Marshall, it's going to be conspicuous if I don't drink, so you're drinking for two tonight.' So Marshall is doing double the amount of alcohol."

"It's sort of our way of addressing head-on the issue of, like, she's going to have a baby, and basically this show is five functional alcoholics, so how's that going to work?" Bays adds.

What's more hilarious than Jason Segel on double the amount of alcohol? Recalling Lily and Marshall's visit to his parents' house in Minnesota, where Lily realizes how big the Eriksen boys are. "We mention that in the premiere," Thomas says. "Lily says, 'I'm staring down the barrel of a boulder-headed Eriksen baby coming out of my hoo-ha. I think you can drink for two tonight. You can have some extra cocktails. I'm going to go through a pretty big ordeal in May.'"

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That's right, Lily will give birth by the end of the upcoming season. "As it turns out, biologically a pregnancy is about the length of a TV season, so we're going to get to see the whole ride and journey that Marshall and Lily take to parenthood," Bays says.

3. Who is Barney's bride? "We're not going to string that along," Thomas promises. In the Season 6 finale, a flash-forward revealed Barney's wedding day. Shortly before the jump, Barney (Neil Patrick Harris) reconnected with Nora (Nazanin Boniadi). Her return causes quite a quandary for Robin. "Robin is watching him chase after Nora, and has an ethical dilemma of like, 'Now I have feelings for this guy again. They're crazy, they're illogical, but there's chemistry,'" Thomas says. "'Do I stamp them down and not tell him so he can go after Nora, or do I possibly screw things up and throw my feelings into the mix?'"

Thomas adds that there will be more than just the main love triangle. "Who's Barney marrying? There will be several choices. It's a little bit of a Mamma Mia in Season 7."

How I Met Your Mother returns Monday, Sept. 19 at 8/7c on CBS.