SPOILER ALERT: Do not read if you have not yet watched “The Beginning is the End is the Beginning,” the Season 3 midseason finale of “This Is Us.”

The third season of “This Is Us” has entered into its holiday hiatus but, true to form, it didn’t go out without one more big twist.

Kevin (Justin Hartley) and Zoe (Melanie Liburd) traveled to Vietnam to learn about his father’s past during the war. They learned that although Jack always said his brother Nicky (Michael Angarano) died in the war, his name was not among the list of the fallen soldiers. But the show didn’t leave it there, instead flashing to a previously unseen house, with an older man shuffling around in the background and envelopes addressed to Nicholas Pearson stacked on a table.

So, not only did Jack’s little brother not die in the war as the Pearson patriarch had led his family to believe — he didn’t die at all.

“We loved that Kevin was going to Vietnam in search of one thing — his father’s war story and his father’s relationship with the woman wearing the necklace in the photos — and he ends up answering a question he didn’t even know he should be asking, which speaks to the unexpected nature of life,” co-showrunner Isaac Aptaker tells Variety.

Nicky’s story was not the only one into which the midseason finale, entitled “The Beginning is the End is the Beginning,” provided insight. The flash forward sequence with Randall (Sterling K. Brown) and Tess (Iantha Richardson) was also extended to get a glimpse at Beth (Susan Kelechi Watson), revealing that the three were all going to see “Randall’s mother.” The reason why is still unknown for the time being, but Aptaker confirms that it is Rebecca (Mandy Moore) they are visiting, not his “long-deceased, biological mother,” despite the vague word choice.

Here, Aptaker and co-showrunner Elizabeth Berger talk with Variety about the revelations learned in “The Beginning is the End is the Beginning,” including when Kevin will learn what the audience has found out about his uncle, why they chose to reveal future Beth in this episode and how they crafted Randall’s debate speech.

At what point did you decide Nicky was not going to be dead after all and why did you feel that was a more compelling story?

Aptaker: That was always part of the plan, pretty much since we conceived of the character going to Vietnam and everything. Jack has always been a guy who’s had these secrets and these parts of his life that he can’t talk about, so it always felt to us that there was something big there.

Berger: We loved the idea of figuring out a story where something so complex happens in Vietnam that there was this fractured relationship between brothers, and we look forward to telling that part of the story when we return.

Did you tell Michael the full plan when he signed on for the role?

Aptaker: We told him the whole story of Nicky right away, pretty much from the moment we called him and offered him the part. We wanted him to understand the trajectory of this guy and how he pulls in and out of the Pearsons’ life.

The show has often said Nicky “lost himself” in the war, but that’s coming from Jack’s perspective. Are there any elements of his behavior in Vietnam that you feel actually revealed the true Nicky, unencumbered by his father or even by Jack?

Berger: We always saw it as this very sensitive kid got thrown into this really terrible situation that was more than he could bear. That’s the kid [Jack] has always known, and that’s the kid that was sent to war, and that’s the kid that breaks when he’s out there. I think we believe that the true Nicky was really this sweet, innocent guy, and the war destroyed him.

Nicky’s death isn’t the only thing Jack has lied about when it comes to Vietnam, but it’s much bigger thing to keep from his family.

Berger: Jack holds himself to such a high moral compass, and he has such a sense of right and wrong, when things get a little murky, those can sometimes be the trickiest situations for him to navigate, and obviously everything out of Vietnam and war is murky, so it plays right into that part of him that really struggles with that sort of uncertainty. It’s obviously a really complicated thing to keep from your family, but at the same time it felt very in-line with Jack’s character.

The audience currently knows more about Nicky than Kevin does. Is the plan to keep the audience ahead through flashbacks for awhile or catch him up quickly?

Aptaker: We’re going to be pretty much experiencing the journey with Kevin from now on, except for that one little tease that you got at the end. And we’re going to dive into this immediately when we get back — that’s what the immediate back-half of the season is about. Kevin, having been given this little nugget of information as he’s leaving Vietnam, what’s he going to do with it? It’s the vaguest of leads, but how is he going to use it to learn about his uncle? Definitely by the end of this year we’re going to have all of the answers in terms of what happened to Nicky.

How closely connected are the past timeline scenes in the final montage of this episode to the future ones? Is it fair to draw direct parallels between seeing Jack dive into the water when he fears Nicky is injured to seeing Nicky alone in the future, as well as Beth making Randall sleep on the couch, to seeing them physically separated in their future?

Aptaker: Sometimes yes and sometimes no, and that’s always been what I think is the fun of the puzzle and mystery nature of the show. Sometimes what we’re watching in the present is a major, major moment that is going to ripple and affect the future in a huge way, and sometimes it’s a little squabble that will get resolved. I think, much like life, you never know which ones will ripple and change the trajectory of your whole life until you can take a step back at the end and reflect. In the past timeline when Jack is jumping into that water, it’s a major, major moment in both of their lives, and it’s a moment that will be explored in the back half of the season. That’s not something that we’re going to make people wait months and years for; we’re going to get to those questions sooner rather than later.

Looking at the future timeline, how did you decide that Beth would be the next character shown?

Aptaker: We have this master plan of where everyone ends up and how the entire series ends, as well, so we’re no longer debating that in the writers’ room. What we do discuss for hours and hours is how and when to parse out these pieces of information: when is the most exciting, when is the most impactful, when is the most dramatic? There was a lot of speculation that Beth had died or was in some kind of physical jeopardy in the future, and that was never part of our plan for the show. We want people to enjoy those Beth stories without wondering if she was going to meet this untimely death, so it was important to us to show she was OK. But at the same time, that was a packed scene, and there is a lot of information there that asks a lot of new questions.

What were your inspirations for Randall’s speech during the debate? 

Aptaker: That debate scene was what we were building to all season and part of the reason we wanted to tell this story. [We knew] seeing Sterling in that venue and with his incredible acting chops would be so thrilling. And also what we find exciting about this race here is that it’s this guy with this incredible amount of charisma but who’s never done this before going up against this career politician who’s had 8,000 debates, so seeing whether or not Randall’s going to be able to harness what makes us all love him in this very specific circumstance against this guy who knows exactly how to spin things and prod at him. He is a disruptor, which is so interesting in politics right now where people come from all kinds of background. Randall is this outsider, is he going to be able to win over this community?

Is he going to struggle with how to actually deliver on the promises he’s making? Is it more interesting to see him actually struggle?

Berger: It was interesting to see Sterling and Randall in a situation where he is uncomfortable because he is such a natural connector. And then it was so satisfying for us to see him take a moment, realize “OK this isn’t when I’m at my best, when I’m behind this podium. I’m at my best when I’m sitting down on the stage, connecting with people.” And yeah, as much as he’s a disruptor, I’d call him a connector. He reaches out in a lot of ways and it felt to us like he was born to do this.

Aptaker: The more immediate thing he’s faced with by the end of this episode is Randall hasn’t really considered how much it’s going to affect his family and the sacrifices he’s going to have to make as a husband and a father for this all-consuming campaign, a two-hour drive from his house. We’re starting to see the cracks in a really scary way by the end of this midseason finale already.

Berger: They’re definitely going to be tested. Their girls — at least two of them — are at an age where things are only going to get more complicated, Randall is only going to get busier whether it’s politics or something else, Beth has to figure out what she wants to do. There’s a lot going on in that household, so it’s going to be a pressure cooker.

Speaking of Randall’s family, Tess told her parents she thinks she likes girls. How much do you want to actually explore her dating at this point in the story?

Berger: I think kids are a little bit more savvy about this stuff from a younger age than I think even we were growing up, and it’s more naturally a conversation point in their lives. Now that we’ve brought it up, it’s definitely something we’re going to see her dealing with slowly throughout this season and the coming seasons.

“This Is Us” airs Tuesdays at 9 p.m. on NBC.