26 Fascinating Details About Syfy's 12 Monkeys

On June 15, all four seasons of 12 Monkeys—the gripping Syfy series that followed characters like James Cole (Aaron Stanford), Dr. Cassandra Railly (Amanda Schull), Jennifer Goines (Emily Hampshire), José Ramse (Kirk Acevedo), Teddy Deacon (Todd Stashwick), and Dr. Katarina Jones (Barbara Sukowa) as they journeyed through virtually every period in time to prevent the Army of the 12 Monkeys from destroying the world—will be available for streaming on Hulu. Mytour sat down with co-creator and showrunner Terry Matalas, along with stars Schull and Hampshire, to share exciting facts and behind-the-scenes secrets from the show. Warning: Spoilers for the series ahead!

1. The series that became 12 Monkeys had no direct connection to the film at the start.

The television adaptation of 12 Monkeys was originally conceived as a writing experiment by co-creator and showrunner Terry Matalas. “I’d always been interested in creating a serialized time travel series,” he shares with Mytour. “So, I sat at my kitchen table and began crafting something called Splinter.” After completing the first three acts, he passed the script to his writing partner (and future co-creator) Travis Fickett, who wrote the latter portion of what would become Splinter's pilot episode. The positive feedback on the script led it to be sent to the offices of Atlas, the production company behind Terry Gilliam’s film adaptation of 12 Monkeys.

Atlas informed Matalas and Fickett that they had been attempting to adapt the movie into a TV series for years and believed they could achieve this by reworking the Splinter spec script. Matalas proposed a different approach: instead of redoing the entire pilot, they could simply change some character names—'it was always about a woman named Cassie who was a virologist, but his name wasn’t Cole, I think it was Max,' he recalls—and introduce the Army of the 12 Monkeys in the final moments of the episode, then take it from there. 'That just seemed like a really exciting way to reboot,' Matalas says. 'Having the intellectual property gave us an opportunity to expand that world [from the film], but at the same time, we could write it in the tone of what Splinter was. And so the rest is history.'

2. 12 Monkeys drew inspiration from HBO’s True Detective.

Along with changes to the characters’ names, viewers familiar with the 12 Monkeys movie will spot subtle references to the film in the series—such as Jennifer Goines sporting a yellow sweatshirt like Brad Pitt’s character in the movie, and the hospital J.D. Peoples being named after the film's screenwriters (Janet and David Peoples)—as well as tributes to the short film that inspired the movie, Chris Marker's La Jetée. But the show also draws from other sources, including the first season of HBO’s True Detective.

“Some of the strange elements of True Detective found their way into the Army of the 12 Monkeys,” Matalas says. “I always felt that, even though it was a science fiction time travel series, there was also a supernatural/horror angle—that the Army of the 12 Monkeys needed to be eerie, enigmatic, and terrifying, with a kind of raw apocalypse they were trying to bring about.”

3. The creators of 12 Monkeys delved into real time travel theories for inspiration.

Matalas and Fickett made several adjustments to bring 12 Monkeys to the small screen. They started with the film's premise that time is a closed loop—where characters can’t alter the past. 'That didn’t seem like a great premise for an ongoing series,' Matalas says. 'To never see any changes in causality would be a missed opportunity for a long-term story.' Although they explored actual scientific theories on time travel—including using an Einstein-Rosen bridge as one inspiration for the time-travel machine—they didn’t rely solely on these ideas. 'When you dive into quantum theory and parallel universes, you can lose yourself pretty quickly,' Matalas admits.

The pair leaned into the concept of paradoxes—where an object interacts with a version of itself from a different time, causing a catastrophic explosion—and created an intricate mythology for the show, introducing elements like the Red Forest, the Messengers, Titan, the Witness, and of course, Primaries: humans whose existence is intricately tied to time itself. If too many of them are paradoxed, they could unravel time itself—which is the Army of the 12 Monkeys’ ultimate objective.

'There’s the simple sci-fi version: The Army of the 12 Monkeys goes back in time and sets off 'time bombs,' and we have to stop them from detonating,' Matalas says. 'That just felt a bit cliché.' But the writers’ room had a breakthrough when they began discussing the evolution of humanity—and of time, which, of all the species on earth, only humans seem to fully grasp. 'Even though time is a force of nature, the introduction of man could have altered its course. Could we have evolved alongside it?' Matalas wonders. 'So we created a network of people—Primaries—who are part of time because of this evolution, making it feel personal and, ultimately, right.'

4. 12 Monkeys star Aaron Stanford initially auditioned for the role of Ramse before being cast as Cole.

Stanford—whom Matalas had previously collaborated with on Nikita—submitted an audition tape for the role of James Cole, but it got lost. When he came in for an in-person audition, he read for the role of José Ramse, Cole’s best friend. 'We were at a point where we really needed to cast our two leads, so we did a chemistry test with him and Amanda [Schull],' Matalas recalls. 'The second they walked in together, we just knew.'

When casting for the role of Deacon—initially the leader of the West VII gang in the post-apocalyptic world before becoming a traveler himself, described in the casting call as 'a young Ed Harris type'—“we saw every young Ed Harris type in Los Angeles and New York,” Matalas remembers. “And then Todd came in... and he was like, 'F**k this. I’m not going to be that guy. I’m going to be the guy who’s really charming.' And that was it—he was the one.”

Matalas says they found exactly who they wanted for every role in the show. 'Barbara [Sukowa] was the only person we considered for Katarina Jones. We read some incredible actors, well-known names, but there was something perfect about her—and she even did her audition on her iPhone,' Matalas shares. 'Same with Jennifer Goines. We saw a lot of people, but the only one I ever really connected with was Emily Hampshire.'

Throughout the entire series, Matalas wrote two characters specifically for the actors who ended up playing them. 'The first was Hannah Waddingham, who played Magdalena,' Matalas says. 'We said 'Hannah Waddingham type from Game of Thrones' in the casting call, and then we got her. And the only person I ever thought of for Athan was [Battlestar Galactica's] James Callis.'

5. After securing the role of Jennifer Goines in 12 Monkeys, Emily Hampshire consulted with a psychologist.

On the advice of a director she trusted, Hampshire chose not to watch the film version of 12 Monkeys before auditioning for Jennifer Goines. It turned out to be the right decision: 'Terry [Matalas] told me, ‘We cast you because you didn’t try to mimic Brad Pitt. You created your own version,’' Hampshire recalls. 'I felt deeply connected to the character on the page—I understood her logic completely. It actually felt easy for me, which is rare.'

Once cast, the show hired a psychologist to ensure that Jennifer’s dialogue was authentic and to consult with Hampshire about the character. 'He explained that many people with mental illness don’t have the societal filter we do—they just speak the truth, like children,' Hampshire shares. 'That’s how I always viewed Jennifer—as someone who tells the truth. Whether you label it mental illness or not, to her, it’s just the truth. That’s the essence I focused on.'

6. Amanda Schull studied virology after being cast as Dr. Cassandra Railly in 12 Monkeys.

Similar to Hampshire, Schull refrained from watching the movie before her audition. 'I had seen it years ago but didn’t revisit it before auditioning because I didn’t want [Madeleine Stowe’s] performance to influence me,' she explains. However, after landing the role, Schull rewatched the film and delved deeply into virology research. 'I studied journalism in college, so I like to gather all the facts, even if they don't always impact the surface-level details,' she shares.

For episode three, where Cassie is in Haiti fighting a virus outbreak, 'I researched various viruses, their side effects, how to properly remove gloves, and that was useful,' Schull recalls. 'But some of the other details wouldn’t affect my performance or the dialogue. It was good to know, but we eventually veer into this entirely fictional world with a virus that’s unlike any real one. I tried to stick with the facts, but then realized I had to pave my own path.'

7. Hampshire's toughest day on 12 Monkeys was her very first one.

The first day on a new set is always daunting for any actor. Normally, productions will schedule simple scenes—'like walking across the street'—to ease the actor into things. But not on 12 Monkeys. On Hampshire’s first day, she had to deliver complex dialogue and threaten a restrained Stanford with a scalpel for the episode 'Mentally Divergent.'

Hampshire had never been part of an hour-long drama before. 'I was used to working on indie films, and this was the fastest pace I had ever encountered,' she admits. 'For me, everything about Jennifer was in the way I moved. The director asked me to do a walk-and-talk with Cole—you start here and end there. I just couldn’t get all my lines out in that short span. I was desperately trying not to cry, and in the end, I did end up crying, but tried my best to hide it,' she says.

Eventually, Matalas pulled her aside and encouraged her to do things her own way. 'It was a terrible day, but it was also a huge learning experience for me,' Hampshire reflects. 'I learned everything about doing the TV show that day.'

8. According to Schull, 12 Monkeys' time travel chair was a 'death trap.'

At some point, most of the main cast members of 12 Monkeys had to run up a set of stairs and hurl themselves into the time travel chair to splinter. Schull describes it as a dangerous ordeal: 'Every one of those steps had a tiny lip—barely noticeable to the eye but capable of tripping you up as you went up or down,' she recalls. 'The stairs were steep, and when Cassie had to run up or down them in heels—urgent, as if rushing toward a disaster that needed time travel—my heels would always catch. Plus, the railing was just a chain, so when I tried to grab it for support, I would almost fly off the side. I’d end up hurting my calf, pants, or shin every single time I rushed in or out of that chair.'

The chair itself wasn’t exactly a smooth ride. 'The first time you sat in it, you’d end up flying backward—you wouldn’t expect it to stop,' Schull recalls. 'There are strands of my hair forever trapped in the headrest of that chair. It truly was a death trap.'

9. The costume department of 12 Monkeys faced numerous obstacles throughout the series.

'Like the characters on our show, we’re constantly up against time,' costume designer Joyce Schure explained to Mytour when we visited the set last year. Depending on the time period, the team often had to hunt for pieces—usually at thrift stores—or source outfits from costume houses. But for the main characters, multiple versions of intricate costumes had to be designed and created, not only for the actors but also for stunt and photo doubles. When shooting outdoors, the costumes had to be lined with felt or fleece to keep the actors warm. And, naturally, the costumes had to be functional. 'Cassie’s dresses had to be gorgeous, but she also needed to be able to chase down a bad guy—and that applied to her shoes as well,' Schull says. 'Every single elegant gown posed its own set of challenges.'

Even with the ever-present time crunch, the costume department didn’t cut corners on the details. One of Schull’s costumes from the fourth season—a 1940s dress—had a low-V back adorned with 'this beautiful body chain that draped across the back, with a single pearl hanging down,' Schull describes. 'When I ran or moved, the dress would fan open, revealing gold and cream art deco paneling on the front. It was incredibly intricate and beautiful.'

In a post-apocalyptic world, clothing could never look fresh off the rack—so clothes meant to represent the year 2043 were sent to the breakdown department. Here, they employed various techniques to give the garments an aged look, like stuffing kidney beans into the pockets and sanding them to add texture, or washing leather to weather the fabric. For the majority of the series, every piece was done by hand. However, during the fourth season, the department discovered a time-saving trick when they had to age a large number of clothes quickly: 'We learned that you can use a cement mixer, fill it with rocks, and let it beat up the clothes,' Schure explained.

Each character in 12 Monkeys has a distinctive costume style, with elements of that style appearing in every outfit, regardless of the time period. 'Take Jennifer, for example—she’s always a double sock girl, always wearing tights with double socks,' Schure explained. Sometimes, the actors themselves would have a say in their costumes. Hampshire worked closely with Schure on her 1920s outfits, including one that was inspired by the poster for Charlie Chaplin’s The Kid.

10. Hampshire once filmed a 12 Monkeys scene with a rat—and it pooped in her mouth.

At first, the production team wanted to use a spider for a scene in season one where Jennifer is tortured by the Army of the 12 Monkeys. But since Hampshire has a deep fear of spiders, and Jennifer needed to appear like she was enjoying herself, the assistant directors emailed her to ask how she felt about spiders. Hampshire’s reply? 'I feel like this is never going to happen. No. I’m also deathly allergic!'—which was untrue, but she didn’t want spiders anywhere near her. Instead, they offered her a scorpion and a rat, which she agreed to: 'I was totally fine with anything but spiders, just to make sure I didn’t get any spiders!'

Hampshire had a meet-and-greet with a whip-tail scorpion—'basically the most spider-like scorpion of all scorpions'—in a conference room. Although they filmed a scene with the creature (which can be seen here), in the end, they used footage of a rat instead. As they rehearsed the scene, the rat pooped in Hampshire’s mouth. 'The wrangler was like, 'This was his first thing ever and he was nervous,'' she recalls. 'I just spat it out. I think I had to enter a different kind of zone for that scene.'

It wasn’t the last time an animal caused a mess on set: Terry the tortoise, who played Jennifer's pet in 2043, 'sh*t the bed in his first scene,' Hampshire recalls. 'They had to change all the sheets in Jennifer’s tent!'

11. Schull had to learn to ride a horse for her journey to the Wild West on 12 Monkeys.

In the fourth and final season of 12 Monkeys, Cassie, Cole, and the team find themselves traveling to the Wild West, and that meant the actors had to get comfortable with horses. Schull trained on one horse, but on shooting day, she was paired with a different one. 'My horse was really not into me,' Schull admits. 'It’s easy to look stiff and uncomfortable on a horse, and I was doing my best to look as relaxed as possible while my horse did everything to make me look bad.'

To try to win the horse’s favor, Schull offered him some snacks (with permission from the handlers), but all it did was make him more hungry. 'There’s this one scene we shot right after that,' Schull recalls. 'Aaron and I are sharing a thermos of water, talking about what we need to do, and the horse was in the background. He was supposed to stand still, but after I gave him carrots and celery, he became absolutely ravenous. He started munching on a tree, and nobody could stop him.'

As the day went on, the horse became tired and easier to control, but the situation was still stressful. 'If we had all the time in the world, it probably wouldn’t have been so intense, but with limited light and so many scenes to shoot, the pressure was on,' Schull says. 'You just want to be the cowboy you’re supposed to be, but working with animals doesn’t always go as planned.'

12. On the set of 12 Monkeys, there was no shortage of pranks and moments of uncontrollable laughter.

Despite the serious tone of 12 Monkeys, the cast and crew made sure to enjoy themselves during breaks between long shooting days. 'The lighting setups took forever—longer than anything I’d experienced before, because the lighting really felt like another character,' Schull explains. 'No one ever disappeared to be alone in their trailers. Everyone hung around and chatted.' There were spontaneous dances, impromptu singing, and even made-up games to pass the time. And, of course, they had fun pulling pranks on one another.

Schull once grabbed Hampshire’s stuffed animal and took photos of it with Hampshire’s phone—an adventure that spanned the set. Hampshire recalls that Matalas had a particular habit of sneaking gum wrappers and pistachio shells into her shoes and purse: 'Not a day went by that I didn’t find trash in my shoes when I went to put them on. That kind of stuff keeps you going.'

While the cast mostly kept their composure, long shooting hours sometimes led to hilarious outbursts. One time, when Cassie was supposed to be performing surgery, Schull realized she didn’t have enough surgical props to make the scene look believable. Sukowa and Hampshire had a field day teasing her—'Barbara said it looked like I was digging a hole in [the patient’s] stomach'—and soon, the laughter became so uncontrollable that production had to be paused. 'We were crying with laughter,' Schull says. 'They had to bring in makeup to clean us up.'

During a late-night shoot for a key scene in season three, Schull cracked a 'really vulgar joke,' which sent Sukowa into a fit of giggles. 'Barbara’s laugh is so infectious,' Schull recalls. 'The two of us couldn’t stop laughing, and every now and then she’d repeat the joke and start laughing all over again.'

13. Tatiana Maslany, star of Orphan Black, shared some invaluable advice with Hampshire on how to portray multiple versions of herself in 12 Monkeys.

Throughout 12 Monkeys, Hampshire portrays Jennifer in two timelines—2016 and 2043—transforming into Old Jennifer required up to five hours of makeup. 'You couldn’t pay me enough to be a Klingon,' Hampshire jokes about the discomfort of the prosthetics, which were glued to her face. 'They were so itchy and uncomfortable, and taking them off was a challenge. But for the experience of becoming Old Jennifer, it was totally worth it.'

For the scenes where young Jennifer interacts with her older self, Hampshire sought guidance from Tatiana Maslany, who won an Emmy and earned a Golden Globe nomination for playing multiple characters in Orphan Black. 'The best advice she gave me was to play the character driving the scene first,' Hampshire shares. 'Once the pace is set, it’s locked in—you have to match that. So start with the character that’s leading the scene, try it out, then do the other side.'

14. The time-bending chase in season 3 of 12 Monkeys was accomplished in just eight hours.

In an extraordinary sequence from season three, Cassie and Cole chase their son, Athan, down the same street across three different time periods. Initially, pulling off this complex scene seemed nearly impossible, both in terms of time and budget. But the cast and crew completed it in a single eight-hour shoot. 'We collaborate closely with our production team to stretch the limits of what our budget allows,' Matalas explains. 'For this sequence, we dressed the area in three different time periods, but by gradually advancing the street, we minimized the need for extensive redressing. We also shot at various times of day. It’s all about smart production.'

15. A scrapped sequence from season 4 of 12 Monkeys would have seen Cassie journeying into space.

Yes, you read that correctly. 'It would have involved sending Cassie to the post-apocalyptic International Space Station for 45 seconds to retrieve some crucial data from a hard drive,' Matalas explains. 'It was a fantastic concept that made sense within the story. It would have been really intense, knowing that people had died up there and it had been years since anyone had been there.' Unfortunately, due to time constraints, the sequence had to be cut. 'If we had just two more episodes in Season Four, we could have made it work,' Matalas adds.

16. On average, each episode of 12 Monkeys featured 60 to 75 visual effects shots.

'Some episodes pushed that number higher, with 100 to 125 shots, while others might include as few as 30,' Sébastien Bergeron, founder and VFX supervisor at Folks VFX, wrote in 2017. 'Most of the work involved creating unseen environments, but there was a range of tasks: futuristic cityscapes, a time-traveling metropolis, characters meeting their past selves, explosions, destruction, and a vast array of FX and particles—pretty much all visual effects you can think of.'

For the season three premiere, one particularly challenging shot required Folks VFX to create a post-apocalyptic version of Times Square. 'We filmed a crane shot in a field using a blue screen, where James Cole steps onto a decaying bus and discovers an overgrown Times Square,' Bergeron described. 'This was a particularly tough scene since every element in it was entirely computer-generated.'

17. The different time periods on 12 Monkeys were shot with distinct styles.

'When dealing with multiple time periods, you get the opportunity to completely transform the visual style of your show,' explains Matalas. 'The '70s might feel like a Polaroid, while the 1940s can have a rich, saturated look'—a period he personally loves to revisit. 'It’s pretty awesome.' The show has received multiple cinematography nominations in both the U.S. and Canada, with Boris Mojsovski, who joined in season two, winning an American Society of Cinematographers Award for his work on the season three episode 'Thief.'

18. Hampshire and composer Stephen Barton co-wrote a song for the final season of 12 Monkeys—and recorded it at the iconic Abbey Road Studios.

In the second episode of Season Three, Jennifer Goines (as J.H. Bond) releases a track titled 'Jones, Pourquoi C’est Si Long?' (or: 'Jones, What’s Taking So Long?'). Hampshire ad-libbed parts of the song, which made it into the episode—and quickly became an on-set favorite. 'Everyone started singing it,' Hampshire recalls, 'and that’s when Terry said, 'I think we need to write Jennifer a song.' Hampshire wrote the French lyrics, while Barton composed the music. The song was recorded at Abbey Road using period instruments. It featured in the episode 'Die Glocke,' where Jennifer also serenaded a certain führer with Pink’s iconic anthem 'U + UR Hand.'

Other songs were considered for the scene, including one from The Sound of Music. However, 'U + UR Hand' was one of Matalas’s favorites. 'I was hesitant to pitch it because it would reveal my workout playlist,' he jokes. 'But I genuinely love that song. It’s this driving anthem—perfect for the moment.'

19. Matalas’s favorite scene to shoot came in the second episode of Season 4, titled “Ouroboros.”

According to Matalas, "Ouroboros" served as a love letter to 12 Monkeys. 'My favorite moment to film was when Jones and Cole witness the first splinter in 402,' he recalls. 'It’s one of those rare moments in time travel shows, where you have these experienced travelers—worn down, emotionally shattered—watching their younger selves embark on a journey as they approach the end of their own. It was an incredibly powerful scene to shoot and score, and it remains one of my most cherished moments in the series.'

The most difficult episode to film, according to Matalas, was the two-part finale of 12 Monkeys. 'The finale was monumental, and I was directing it,' he explains. 'The battle in Titan with Cole, Ramse, and Deacon fighting the Army of the 12 Monkeys was intense. We shot it at a decommissioned oil plant in Sarnia, Ontario, which had a perfect, time machine-like aesthetic. But we only had eight hours of night to shoot it. My DP, Boris, and I were running around like guerilla filmmakers trying to get everything, and we did—but it wasn’t until we were deep in editing that we realized we had enough to make it work. It was nerve-wracking, to say the least.'

20. In the 12 Monkeys series finale, Cole and Ramse were originally set to take on the Army of the 12 Monkeys to a Journey song.

In one memorable scene of the series finale, Cole and Ramse race towards the Army of the 12 Monkeys, with Bill Medley and Jennifer Warnes’s "(I've Had) The Time of My Life" playing on the radio. While the song was a perfect fit for the scene, it wasn’t Matalas’s first choice. 'Initially, we were going to use Journey’s 'Don’t Stop Believin’,' but Journey turned us down,' Matalas recalls. 'We started searching for an alternative, and then ' (I’ve Had) The Time of My Life' came on my playlist. I had my editors test it in an early cut, and it was ideal. I wasn’t sure we’d get approval, but it came through. It was beyond perfect, and I’m honestly grateful that Journey said no—it ended up being so much better.'

21. 12 Monkeys was filled with subtle nods to future plot twists.

'There are so many,' Matalas shares. One example is the revelation in season four that Hannah is Cole’s mother, which he had disclosed to Brooke Williams on her very first day on set. 'She always knew and started adopting little mannerisms,' he says. As they approached the series' end, the team began planting small clues. 'That’s why the first episode of season 3 starts with Hannah and Cole teaming up. They’re very alike,' Matalas points out. 'Jones calls [Hannah] a little sh*t, Hannah calls [Cole] a little sh*t, Cole calls Athan a little sh*t. It’s this generational thing—a charming insult they pass down.' He thought it was an obvious hint, considering the odd phrase, but yes, it was all there. Also, keep an eye on Athan’s visions in season 3, where you’ll spot glimpses of Titan wreaking havoc—a hint to the finale’s events.'

22. When filming wrapped for 12 Monkeys in Toronto, the evidence board deeply moved Matalas.

Once filming for 12 Monkeys concluded in Toronto, there were still scenes to shoot in Prague. However, Matalas recalls, 'It felt like the show ended on those soundstages. I remember walking through them after we wrapped, with Amanda, both of us saying goodbye to the sets we’d been on for four or five years. I thought for sure the tears would come when I saw the time machine for the last time. But it was the evidence board that hit me hardest. It had four seasons of stories pinned to it. It was all this history, and that really, really got to me.'

23. Schull and Hampshire ended up taking home several props and costumes from the 12 Monkeys set.

Schull owns all of Cassie’s coats—'I don’t think her coats received nearly enough attention; the downside is that I live in Los Angeles, where I don’t get to wear any of them'—and a Raritan National Laboratory plaque from the set. 'But the most meaningful gift I received was Cassie’s watch with the original scratch on it,' Schull shares.

Hampshire has kept several of Jennifer’s costumes, along with the E.T. and chestburster alien props from Jennifer’s role as J.H. Bond in 1920s Paris. However, her most cherished item isn’t a prop: It’s a sock monkey created for her by the costume department, reflecting Jennifer’s trademark double-sock look. 'Inside, it’s filled with pieces from all her costumes,' Hampshire reveals, 'including fur ears and buttons from her outfits.'

24. Matalas took home the 12 Monkeys time machine—and one other, eerier prop.

Although the time machine is no longer in his possession, Matalas has retained its most crucial element: the chair, which now resides in his garage, alongside the Delorean from Back to the Future that he restored. But that’s not all—also in his garage is the body where the virus originated (the split-in-two corpse of Olivia, the Witness). 'I still have that body in my garage, and I have no idea what to do with it,' Matalas admits. 'It’s in a Tupperware™ case. I opened it up the other day and thought, 'Oh god!' He knew back in Season 1 that the virus wouldn’t come from Cole, but from the Witness.

25. Matalas always knew what the final scene of 12 Monkeys would be, but not necessarily how they'd get there.

'I would say, during the first half of season one, we had a clear idea of the season’s arc, but we hadn’t fully mapped out the entire series,' Matalas reflects. 'It wasn’t until season two, when Cassie was pregnant and we realized we were at the midpoint, that the rest of the story began to unfold. At that point, we had to figure everything out to avoid being caught off guard. I had a hunch that yes, Cassie is pregnant, but could the child be the Witness? I knew that couldn’t work as is, and there had to be another twist.' He loved the idea of Olivia (Alisen Down), leader of the Army of the 12 Monkeys, transitioning from 'hating the Witness' to discovering that she is the Witness.

After finishing season two, Matalas and the writing team broke out the white boards to plot the remaining episodes—and the final scene was exactly what Matalas had always envisioned: Cole and Cassie’s reunion. 'The ending was always meant to be this: You’d think Cole was erased, but in the final moments, he would return to her. The surprise twist of 12 Monkeys would be that it actually ends on a happy note, leaving the audience fully satisfied,' Matalas shares.

26. Matalas firmly believes that Cassie and Cole are not in the red forest.

The final shot of 12 Monkeys shows a red leaf—a symbol that echoes the timeless Red Forest seen in the Army of the 12 Monkeys. 'The red leaf was designed primarily because the show had hinted at an ending that might not be happy,' Matalas explains. 'So, if that’s the ending you prefer—one with a darker, more twisted twist—you could interpret it that way. You could argue that Cassie never turned off the machine in Titan.'

Matalas doesn’t interpret the ending the same way. 'I think it’s clear that they saved the world, and it’s just fall, with the red leaf being the symbolic representation of the show,' he shares. 'However, there are some people, even within our own crew, who believe they’re still in the Red Forest. I don’t think that theory holds up. I don’t understand why, in the Red Forest, Cole would need to kill himself or why Jones would have to die. That doesn’t make sense to me. But if you want to believe that, go ahead!' As Jennifer Goines once remarked, the right ending is the one you decide on.

This article was updated in 2019.