Though Steve Rogers’ presence was very much felt in the Agent Carter finale, it was another Captain America character who made a surprise cameo in the closing moments of the episode.

Under the mind control of Johann Fennhoff, aka Dr. Faustus (Ralph Brown), Howard Stark (Dominic Cooper) took off in his plane, believing that he had finally located Captain America’s (Chris Evans) body in the Arctic—though in truth he was on a one-way trip to drop what amounts to a rage gas over Times Square. Fortunately, Peggy (Hayley Atwell) was able to talk Stark down, and the SSR took Faustus into custody, where he met his new cellmate, Dr. Arnim Zola (Toby Jones). Hail Hydra! How’d the surprise cameo come together? EW has the exclusive scoop from Captain America scribes Christopher Markus and Stephen McFeely: (And check here for more scoop from showrunners Tara Butters and Michele Fazekas.)

ENTERTAINMENT WEEKLY: How did the idea to have Toby Jones appear in the finale first come together?

STEPHEN MCFEELY: We’ve wanted Toby Jones to appear since we pitched this show. We did not know exactly where it would happen or where he was on his timeline, but we always wanted to show you how Hydra started it’s [reach within S.H.I.E.L.D.]

CHRISTOPHER MARKUS: People having seen [Captain America:] Winter Soldier know what happens to S.H.I.E.L.D., so we didn’t want to deal with that as a plot point because it’s a given, but just to give them a delicious little taste of the story that they know happen. Also, it has become clear weirdly that there are four characters who span the entire marvel Cinematic Universe: Steve, Bucky (Sebastian Stan), Peggy and Zola. We wanted to see Toby’s body again.

MCFEELY: We just saw his head last time.

Was this also your way of saying this is leading to the Winter Soldier program since Dr. Faustus works in mind control?

MCFEELY: Yes, I think it is safe to say there is a connection.

MARKUS: It’s a bit of a convoluted timeline in that in the first Captain America, Zola was captured in the same mission where Bucky fell off the train. Theoretically, a division of Hydra—possibly a Russian division of Hydra—went and got the body while Zola was in custody. Zola had already done something to Bucky, and experimented on him that made him beyond human, which allowed him to survive the fall and make him worth doing the research on. They kept him in stasis until Zola was able to have a little bit of freedom from the American government, at which point he maybe brought his new friend Johann Fennhoff to handle the mind control part of the Winter Soldier project.

MCFEELY: That’s how we see it. I’m not positive that is gospel at the moment, but that’s how we sleep at night.

Why was this an important moment to get to since it really links so many other big moments together?

MCFEELY: The idea that we can link all these movies because we’re the ones writing them allows us to plant stuff that other people might not plant because maybe they don’t care or might not see the connections. Because we have no lives and this is what we do now, it allows us to make important things that people might not find important. Zola wasn’t always going to be in Winter Soldier, but we needed a good way to have this exposition dump in the middle of the movie. We love Toby Jones and thought that would be a great idea. When we got the chance to do the television show, we wanted Toby Jones in that too.

MARKUS: It’s a weird balance of this primal pleasure in the way everything interconnects, but you have to balance that with making the world too small, like only five people are responsible for everything that ever happened. Because this is the Captain America section of the Marvel Universe, it felt valid and more fun.

MCFEELY: It was [showrunners] Tara Butters and Michelle Fazekas who decided to put him in jail. We said, “Let’s have him!” and they figured out where to put him.

Were there other alternate endings you considered when it came to Zola and Faustus?

MARKUS: The debate is when he went from prisoner to collaborator. In 1946, he was probably still a prisoner, but there was some debate of what side of the bars he’s on.

MCFEELY: Was there a version where he’s wearing a little I.D. badge that says he’s working for the Americans now?

MARKUS: But that made the U.S. government too stupid. [Laughs]

MCFEELY: One could argue that they ought to at least be in adjoining cells, but there are certain practicalities to shooting.

If there is a second season, would you delve into the Winter Soldier program or is that something you want to keep for the movie side of things?

MCFEELY: It’s a little TBD on that. Because of what we know about Winter Soldier and that Hydra was working all along with S.H.I.E.L.D., it necessitates Peggy having a lot less information than the audience has, so I’m not sure how long we could keep that up—where every time Toby Jones smiles at her, we know something and she doesn’t. We don’t know exactly what Season 2 is yet, or if there is one, so I don’t have a great answer on how we would use him, if at all.

Does this open up the possibility of seeing Dr. Faustus in the future?

MCFEELY: He’s easier, yeah.

MARKUS: Anybody who doesn’t die can come back, and even some people who do die can come back, as the movies have shown. It just depends on where we want to go with the possibility of another season. There’s something very appealing about not picking up two days after the first one ended, but taking a jump. We know Peggy lived well into Winter Soldier, so we have that much time to deal with. I don’t think we’d jump to 1980 when she’s 70 years old, but we can move in time, so it’s hard to say who comes back and who doesn’t.

MCFEELY: Let’s be generous to ourselves. Maybe ABC wants to do this again, but do they want to do it for 8, 10, 13 episodes? That will determine what stories we tell.

Is there anything in the first season that you didn’t get to do that you really wanted to?

MARKUS: When we were figuring out the show and the backstory of the show, we had a really nice story about who Peggy is and where she came from. We just didn’t have any time. I would love to tell that story.

MCFEELY: That’s one of our strongest ideas for the second season: What makes Peggy, Peggy? We like what Peggy is, but if you ask some hard questions, you might wonder: but why is she that way? We have some thoughts on that.

So her pre-Captain America days?

MARKUS: Yeah, but that doesn’t mean we need to tell [it in] flashbacks.

MCFEELY: It just means that problems from before she even joined the SSR might come back and revisit themselves, allowing you to explore her past.

MARKUS: What—other than tremendous ability and self-confidence—motivates a woman in 1940 to put up with this much resistance and danger? Why that path? Because it’s not an easy one. There are stories to be told.

MCFEELY: Other than that, it’s been a nice combination of most of the things we pitched fell into place. We knew we were going to get Faustus, things were going to go wrong with his plan, he’d have to readjust and get brought into the SSR in a tricky way. He was going to be in Russia and get brought in behind the walls. We always knew Peggy was going to pour Steve’s blood out. That was a big moment for us. We didn’t know where it was going to happen. Tara and Michele pretty cinematically put it on the Brooklyn Bridge. We always thought the idea that Peggy could be the custodian of Steve and have one final chance to say goodbye to him, thus—in many ways—creating the biggest problem of the Marvel Cinematic Universe, which is that everybody wants to replicate Steve’s [abilities]. That’s how you got the Hulk and things like that. We liked the idea that it was on Peggy Carter doing the right thing.

What came with the decision not to delve into the husband storyline since it was such a big hint dropped during Winter Soldier? And do you have a sense of who it is?

MARKUS: We have potential senses. You lob it off too early and suddenly you’ve got a couple show.

MCFEELY: This was the season where she says goodbye to Steve. I’m proud of the fact that Captain America hovers over this show, but hopefully in an organic way, and we’re not shoving him in there all the time. But we knew by the end that she should say goodbye to him. In a second season, she could be freer to have those conversations about a life after him.

MARKUS: Also, you’re doing a show about this incredibly independent woman and you’re always talking about the man she left behind. It becomes a little contradictory. We know her husband was in the war and he was saved by Captain America. He could be a baker. [Laughs]

MCFEELY: Being saved by Cap could be very tangential.

Should the series not be renewed, would you consider doing another One-Shot?

MCFEELY: If it doesn’t get picked up, I mean you never know. It would have to be a really perfect 12 minutes.

What do you want audiences to take away from this season?

MCFEELY: I think a lot of people were surprised by how good it was. It’s clear that Marvel really was invested in her. I hope it’s clear that we and the writing staff were invested in her. I think it’s really clear that Hayley is a very good actress who knows this character backwards and forwards. Whether it comes back or not, I think people will look back on this fondly and say this was well worth it and they got to learn a lot more about a character who holds a resonance throughout the MCU.