We're five weeks into Joss Whedon's Agents of S.H.I.E.L.D., the first television show to bring the wildly successful world of Marvel movies to the small screen.And just as in the Marvel Cinematic Universe, where characters from Iron Man, Thor and Captain America cross over and even team up, we've seen elements of the films make their way into episodes of S.H.I.E.L.D. early on. Not only has the Extremis technology (which powered the villains of Iron Man 3) shown up several times to cause problems for our heroes, but Samuel L. Jackson appeared in the second episode. What other special appearances or crossovers might be in store?

WIRED sat down with Jeph Loeb, Marvel’s head of television and an executive producer of ABC’s Agents of S.H.I.E.L.D. to talk about the potential for more Marvel movie cameos, as well as castmembers Iain De Caestecker and Elizabeth Henstridge, who play the dynamic tech duo Fitz and Simmons (aka Fitzsimmons). Oh, and a cowbell. So whether or not we got answers, we did get tinnitus. Read on.

[A cowbell on the interview table is being rung with enthusiasm as I enter]

WIRED: Can we hear about the cowbell? How that’s important for S.H.I.E.L.D. operations?

Jeph Loeb: That’s a level eight question, sorry. Cowbells will be playing a very important arc in the season finale. [Laughter]

WIRED: I’m going to tease that, and it’ll become a thing on the internet.

Loeb: Yes. More cowbell at S.H.I.E.L.D., hashtag.

WIRED: Jeph, how will the show be dealing with the ongoing productions of the Marvel Cinematic Universe?

Loeb: Carefully.

WIRED: For example, when Thor: The Dark World comes out, can we expect a tip of the hat from S.H.I.E.L.D.?

Loeb: Wouldn’t that be fun? ... Look, it’s never been done before, which is kind of incredible when you think about how many dramas and how many big movies have been out there. There certainly have been television shows that have been spin-offs from movies, but to have an ongoing, ever-changing mythology which is happening first in the comics, and then in the motion pictures, and the movies are coming out at a rate of two a year – these giant tent-pole films that are reaching a billion dollars at the box office, which means that that mythology is being shared around the world. For us to tell stories that exist with not only similar characters, but often shared characters – beginning with Clark Gregg as Agent Coulson – sometimes we have to be very careful. We have to dance between raindrops. But other times, if we know something is going to happen: Can we use that? Can we make that have an impact on the show? And I think we’ll see some of that in a very interesting way.

Elizabeth Henstridge: [teasing] Wouldn’t that be interesting?

WIRED: We’ve already had some very special guest appearances from the Marvel Universe. Can we expect a few more?

Loeb: Well, I think folks know that Titus [Welliver], who played Agent Blake, is coming up in episode six [on November 5]. The short answer is yes. But we’ve said from the very beginning, we didn’t do the show in order to make an Easter Egg farm. We want to make sure that if there are going to be characters, things, winks, that come from anywhere, whether it’s the regular mythology of the comics or the Marvel cinematic universe, that it works within the story. That we’re not doing it just to do it. When I look at Cobie [Smulders]’s appearance in the pilot as Maria Hill, it was really important that the person who reintroduced Coulson into the world was Maria Hill. We needed someone who had the gravitas of one of the major characters from the [Avengers] movie being able to say, "There’s a secret, and we’re not going to be able to share that secret with you, but we’re going to take you on the journey with us." ... If you were part of the Marvel family to begin with, it landed for you in a very different way.

The same kind of thing [happened] when we talked about Sam Jackson being on the show. There were obviously a number of places that we thought Nick Fury would have a big impact on the show, but the more we talked about it, [we wanted] was to get him in very early, so that it would kind of christen the show, legitimize it in its own way. And when Sam generously agreed to do the show, there was a moment where, for people who watch the show, it was the wowest of wow they could imagine.

But for us as we were standing there on the set the first day, and he said the words "Don’t let FitzSimmons bring on some damned fishtank," we all just started geeking out, because suddenly we were like "OK, now, now they’re in the family, Director Fury just said ‘FitzSimmons’... so these brand new characters, that didn’t exist in the Marvel Universe, are now firmly entrenched, and it did exactly what we wanted it to do ... which was to basically say, these are five new characters who are joining the family.

On the one hand it’s cool to see Agent Blake, on the other hand we’re introducing new characters in every single show. We will by the end of season one have done 22 hours of S.H.I.E.L.D. stories, we will have told more stories in the Marvel Cinematic Universe than all of the movies combined. So our responsibility becomes greater every day, that we make sure we tell stories that are worthy of the Marvel Universe ... And when you’ve got people like Joss Whedon and Jed Whedon and Marissa Tancharoen and Jeffrey Bell at the helm, we don’t have anything to worry about. The scripts just keep coming in, and getting better and better.

Photo: ABC/Ron Tom

WIRED: Iain and Elizabeth, you’re sharing the traditional role of the "tech genius" with Fitz and Simmons. I like that it’s split – two sides of the same brain is the effect. How do you feel about the technological elements of it? Is it difficult to wrap your mouth around the lingo, or are you techies at heart?

Henstridge: What makes it easier is that we get to play with the funnest gadgets ... Funnest, I’m not 100 percent sure that’s a word, so, yes, I struggle sometimes with the tech lingo [laughs] ... So we just have a great time in the lab. Our lab is filled with all sorts of machines that work, different potions that they make up, like we saw in the pilot ... that kind of thing is great, I love that aspect of our characters. As far as the technical jargon goes, we understand everything that we’re saying, there are advisors on there. The words and the ideas come from a very real place, that could exist in the real world, so once you understand it, it’s kind of easier to wrap your head around it, you learn it like any other line ... Any folder that you see on S.H.I.E.L.D., every single page of that is actual information. It’s crazy. Anytime that we’re leafing through files, every page has to do with whatever it’s meant to do, it’s got all the science in it, all the graphs in it; it’s ridiculous.

WIRED: I was looking at character notes that were originally given to describe some of the characters. For example, Ward is gruff and asocial, and Skye is bubbly and edgy. I was curious what initial notes you had received on Fitz and Simmons, and how you had taken those and worked to make the characters your own?

Ian De Caestecker: The big thing was the relationship between Fitz and Simmons together. How they were very dependent on each other, but they had a very strong bond and they could finish each other’s...

Henstridge: [immediately] ...sentences, you could say.

De Caestecker: They’re extremely unbelievably...

Henstridge: ...great together.

De Caestecker: They’re very excitable, as well. They’re prone to getting very excitable when it comes to science and all things on that side of the world.

Henstridge: When we first went into the audition, we got very little information. We got that they kind of came as a duo, and that Simmons was a biochemist and she was incredibly intelligent, but that’s kind of all I got. That she was young and intelligent. And then you just get the script, that’s specifically for the auditions.

Loeb: We didn’t want to use a scene from the actual pilot for a number of reasons. One of which was that as executive producers we didn’t want to be sick of the scene by the time we were going to shoot it, and we were seeing hundreds of actors from Toronto and London and New York and Australia and Los Angeles... Joss wrote a scene specifically for the audition – basically, the two of them in a very close, trapped space, and they’re going to die. We saw each of them individually, and then we picked pairs. I think what it really speaks to is that Elizabeth and Iain, in their very first reading together, had a kind of chemistry that we weren’t going to be able to manufacture; it just happened. They’re very different sorts of people, and that magic happened right away, and just made it sort of easy.

WIRED: Any chance we’ll ever get to see that scene?

Loeb: Well, they do have those things called DVD extras.

Henstridge: Oh, no!

Loeb: Both of them are horrified by that idea.

WIRED: Some fans are interested in whether there will ever be romantic possibilities here. You guys sort of flirt with it a little, but there’s also a brother-sister vibe. Can you reveal some of the direction on that?

De Caestecker: Fitz and Simmons have already been together for so long, it’s definitely more of a brother-sister thing. If it’s there, it’s always been there. They’re not aware of it, I would say; it’s more that they’re each other’s family. More of a brother-sister. Or maybe an old married couple who have been married for 50 years.

Henstridge: I think it’s also more interesting to play it that way. As an actor I like to be in the same place as my character, and I think right now, Simmons doesn’t ever think that she’ll end up with Fitz romantically, so that’s how I guess we’re both playing it at the moment.

WIRED: We’ve seen the team starting to evolve together. Will we be flashing back to how they got there? Any chance of a Fitz episode? A Simmons episode? Will we see how they first came together – do we get the backstory?

Loeb: Wouldn’t that be great?

WIRED:That’s going to be the title of this piece. "Wouldn’t that be great."

Loeb: We don’t mean to tease. There was a time when television was very much about the only way that you knew what was going to happen next week was by watching next week, and in a world of the 24/7 news cycle, every little thing that we talk about suddenly becomes the next story. And we’re trying to create a world where this is a show that people don’t know what they’re going to get next, and that there is a surprise that’s coming around the corner, and when it comes to be 8 o’clock on Tuesday nights you gather up the family. And while we love all of the tweets, and we love all of our downloads, and everything else like that – I’ve said it before, it would be great if this became a show in which the social media was the family sitting in the living room watching it live. That actually makes it new. Because we’ve now come to a place where even as we’re sitting in the same room, we’re watching two different television shows with people, so we want this to become a shared social experience.

WIRED: Returning to the question of whether we’ll see the individual character’s backgrounds unfold–

Loeb: Every episode tells a little bit more of the story; that’s the fun of what’s going on. So without really giving anything away, each of these characters has obviously a very complicated backstory, and a lot of secrets. Some of those things are going to spill out, and they’ll be fun, and sometimes they’ll be harmful, and so we’re going to be very careful.

De Caestecker: [rings cowbell]