[Warning: The following contains spoilers for the Season 1 finale of A Million Little Things, so read at your own risk!]

A Million Little Things finally revealed who Barbara Morgan is and how she fit into Jon's (Ron Livingston) suicide. The Season 1 finale confirmed that Drea de Matteo was actually playing the mystery woman, despite calling herself Emma Nelson when she was first introduced on the show. She and Jon were involved in a Sept. 11 tragedy that pushed Jon to exile the woman for the rest of his life.

Emma/Barbara was the girlfriend of Jon's college roommate, Dave, who died on Flight 11, which was hijacked by al-Qaeda on its way from Boston to Los Angeles. Jon was supposed to be on the flight with Dave, but he stopped to buy a bottle of wine and ended up being too late to board the plane. Barbara was pregnant with Dave's baby at the time and ended up meeting a first responder named Mitch in the weeks following Dave's death and they fell in love. When Jon found out that Barbara was moving on so quickly, he flipped out and accused her of trying to delete their friend from their lives. After Jon's freakout, Barbara and Mitch decided to raise their kid as Mitch's son, leaving Dave omitted from the picture all-together, which is why she never reached out to Jon again. The survivor's guilt Jon carried from that day forward was a big contributing factor in his decision to commit suicide.

The twists don't stop there.

Flash-forward to present day, after Barbara has told Delilah (Stephanie Szostak) the whole story, and Barbara's 17-year-old son came home. Delilah was shooed out before "Patrick" could see she was there and ask questions, but the end of the episode revealed that Patrick is actually PJ (Chandler Riggs), the young man from the hospital that Rome (Romany Malco) had taken under his wing.

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"I was trying to figure out where my character kind of fit in, and [DJ Nash, showrunner] told me that my character was going to be Barbara Morgan's son, and I was like 'Oh, wow. That is insane because it makes so much more sense as to how it's tied in [to] everybody else's story,'" Riggs told TV Guide of the reveal.

PJ found the memory card with the video of Jon apologizing to Barbara, and that basically told him that Mitch wasn't actually his dad — which sets up a lot of drama for Season 2. PJ's investigation into who he really is will coincide with Delilah welcoming her new baby as Eddie (David Giuntoli) attempts to reconcile with Katherine (Grace Park). However, the end of the finale also saw Eddie confessing something to Katherine that could change their plans to try and make their marriage work again.

TV Guide spoke to A Million Little Things executive producer DJ Nash about the Barbara Morgan reveal, Eddie's confession and what all of it means for Season 2.

Ron Livingston, <em>A Million Little Things</em>Ron Livingston, A Million Little Things

Was this story a mystery that you had fully fleshed out when you wrote the pilot, or was it something that you developed over the course of the season?
DJ Nash: When I wrote the pilot, I did not know the Barbara Morgan side. Before I wrote Episode 2, I had worked all of this out. So, when I wrote the pilot, Channing [Dungey], the network president at the time, she had read my first draft, and she gave me a really smart note, which was, "Is there a way to evoke Jon at the end of the pilot?" And so, I thought of three ideas. One, which we went with, which was having the video of them trapped in the elevator and using Jon's voiceover in that video to sort of voice over the last act of the pilot. There were two other ideas I thought of, that I also only mentioned to my producing partner Dana. One was, maybe the guys all went to this hockey game, and they didn't make it to Game 7 because they got snowed in at O'Hare. ... And the third idea was, what if the guys all were supposed to be on Flight 11, and weren't, and you know, missed the flight, in a similar way to the O'Hare story?

So, on the first day, in the writers' room, where my writing partner, David Marshall Grant, said to me, "Hey, what do you think broke Jon?" I said, "Guys, what do you think of this?" And I pitched out the story that is our finale with O'Hare and everything to do with the Barbara Morgan story. And everyone really dug it...

What was great about that was, we went into Episode 2 knowing the finale. So, instead of just building up with Episode 3, 4, 5, we built Episode 2, then we built the finale. Then we did three, and then we did the [penultimate]. We were building toward the center. ... So we could plant these seeds along the way, like in Episode 4, when Delilah and Jon share in front of Delilah's dad the story of how they met at the airport. We could just plant these seeds and pay them off later.

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Why did 9/11 feel like a more poignant way to do this rather than having Dave die in a straightforward plane crash?
Nash: When we deal with depression, suicide, breast cancer, adultery, and now September 11th, I wanted to make sure that, while we are talking about fictional characters and fictional stories that happened with them, there are people who are affected in real life about all of these topics. So, we wanted to be sensitive and respectful of the people who lost people on that day.

For me, the key to it was Mitch and having this first responder that Barbara meets. That was such an integral part of the story, and certainly an integral part of where we're going with the story. From Mitch's perspective, he meets this woman, falls in love with her. She's pregnant. ... He says, "I'll raise the baby as if it were my own." And she goes, "No. Raise the baby like it's my own. ... I just don't want the baby born under this cloud of this sadness. I want to move forward," which is a choice some might make. So, Mitch's first move is to lie to his child, and he's been carrying this secret for 17 years, and the only comforting thing is the only two people who know the secret wouldn't dare say anything. ... I feel like [with] the September 11th factor that the idea [is] that Barbara is trying to move on from something, where it's so hard because everyone is aware of it, knows about it. ...[ Mitch] lost his whole department, but the idea that they're all dealing with that at the same time, I think is really relevant to the story, and really relevant to understanding why Mitch, who seems at first aggressive and maybe even violent, is really just trying to protect his family.

PJ finds Jon's video at the end of the episode. How does that shape Season 2? What questions is he going to have after he finishes watching what Jon has to say?
Nash: He learns that Mitch is not his dad. ... What I love about our show is that more than one character deals with a similar theme at the same time. We can see how they deal with it similarly or differently. So, the last thing Delilah does is she looks to the kitchen before she leaves, and she sees a father, a mother, and a child, who's been told a lie. ... That's their reality, and it's not a coincidence that she and Eddie and their baby are dealing with a similar dilemma. So I really want to juxtapose those, and have those women continue to know each other in Season 2. You know, for PJ, in some ways, PJ will be the cautionary tale for Delilah and Eddie, by how they decide to play this.

Speaking of Eddie, I don't want to make assumptions about this show anymore. Is he actually planning to tell Katherine about the baby or is he confessing something else?
Nash:
Then don't. He is coming there to tell her something that she needs to know. And he was all but home, but he's being truthful.

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Is Katherine going to be able to respect that honesty, or will this completely undo the progress that they've made?
Nash: It's a really tough thing. What would you do, you know what I mean?... I fought so hard to convince [Grace Park] to do this show, and I'm so glad I did. Because she brings an honesty to Katherine. ... [The writers and I] have consistently put Katherine in impossible situations, like really hard, tough situations, not the least of which is this. I mean we see her look in that mirror as the voiceover says, "Sometimes you have to forget the past and move on." It is all there. She has, somehow, decided that the level that she and Eddie have found now is worth forgiving him for what happened. Yes, he had an affair, but maybe she didn't make him feel special. She's owning her part of it. He's owning his part of it. Everything is there, and you know what? They're doing if for Theo. They're doing it for themselves, and now Eddie comes home, and before he comes home, some piece of information is delivered to her, that is going to rock her world. ... Is she going to rise above it and have to be the big person, like she always is, or is this the time where she's like, "No, you know what? This is too much"? I think our viewers, hopefully, as they watch her, will go, "I would do that," or "I wouldn't do that," or "I don't know how she shows that strength," or "How can she not show that strength?" I want us to look at her the way we have all season, which is in awe of her strength, but totally understanding of her frustration.

A Million Little Things has been renewed for Season 2 on ABC.