Editor’s Note: Spoilers ahead for Zero Day

Summary

Lizzy Caplan in Zero Day brings emotional depth and edge to a conspiracy thriller.

Caplan’s character, Alex Mullen, faces emotional turmoil after a key character’s betrayal and death.

In an interview with Collider, Caplan talks about working with Robert De Niro, director Lesli Linka Glatter and the all too real moments that took place during filming.

When Lizzy Caplan shows up in Netflix’s limited series Zero Day, you know things are about to get interesting. Playing the fiercely independent, razor-sharp daughter of Robert De Niro’s former President George Mullen, the award-nominated actress brings her signature mix of edge and emotional depth to a conspiracy thriller that thrives on secrets, suspicion, and the slow unraveling of trust. Dropping viewers right into the heart of a post-crisis America grappling with the fallout of a catastrophic cyberattack, Caplan tells Collider that “it was a lot of art imitating life imitating art” for a series that reflects on much of what is happening in the world today.
Written and executive produced by Eric Newman (Children of Men) and Noah Oppenheim (Jackie) with Lesli Linka Glatter (Homeland) directing all six episodes, it’s also a series Caplan was more than humbled to be a part of. While she will forever live for the fact that she and De Niro share some of the best moments on screen as father and daughter, the ending leaves things a bit more up in the air for the former first daughter. And while Zero Day ends with enough ambiguity to spark speculation, Caplan makes it clear that this story was always meant to be self-contained. “This was never presented to me as something that might have a Season 2, so I would be very surprised if there was one,” she admits. “Leave ‘em wanting more!”
As for more, Caplan admits she wishes there was at least another scene with her co-star, the reliably excellent and effective Jesse Plemons, who plays Mullen’s political advisor. After the cyberattack’s conspirators including tech billionaires, Monica Kidder (Gaby Hoffmann) and Robert Lyndon (Clark Gregg), found out he wasn’t playing along, they had him killed. It was a moment, Caplan says, left her wanting to do “100 more scenes” with him.
Roger’s Death Opens Up Another Side of Alex in ‘Zero Day’

“I love that they’re these two immensely broken people who cling to each other in the face of everything.”

Roger’s death in Zero Day isn’t just a shocking plot twist — it’s a defining moment for Caplan’s Alex, pulling her deeper into the tangled web of conspiracy and betrayal. For the former First Daughter, Roger wasn’t just an ally; he was a link to her past, an individual who understood her fractured world in a way few others could. After all, he was also her late brother’s best friend. But when Roger chooses loyalty over self-preservation, refusing to betray her father, George, despite the leverage against him, it sets off a chain reaction that exposes the darkest corners of the conspiracy. Yet as Caplan tells us, it also cracks open layers of emotion Alex has been holding back.
“That was a real priority for Jesse and myself, to try to enrich those scenes with as much shared history and shared trauma as we possibly could,” Caplan explains. “Because they really don’t have that many scenes together. There’s just not a lot of real estate to try to convey how deep their history is and how enmeshed they are, and so I would honestly do 100 more scenes just to further explore.”
That shared trauma is what makes Roger’s death hit Alex so hard. It’s not just the loss of her romantic partner, but it’s the loss of someone who truly got her and understood the messy layers beneath her sharp exterior. “I love their relationship. I love that they’re these two immensely broken people who cling to each other in the face of everything, even if that’s not necessarily the wisest thing,” Caplan adds.
When ‘Zero Day’ Became All Too Real for Lizzy Caplan

“People thought that Robert De Niro shooting scenes from the show was just Robert De Niro on the street, giving these rousing speeches to people.”

Image via Netflix

While Roger’s death might have been a shock to viewers, several moments in the miniseries draw parallels to other events that have happened during some very heated political moments in U.S. history. With the fiction of Zero Day cutting a little too close to reality, Caplan found herself in moments where the lines between the scripted thriller and real life blurred in eerie ways.
“Yeah, there were, and actually, there have been so many since we wrapped as well,” Caplan admits when asked if the show ever felt too real. One moment that stood out? People couldn’t tell when De Niro was acting or just being himself one New York afternoon. “People thought that Robert De Niro shooting scenes from the show was just Robert De Niro on the street, giving these rousing speeches to people. Then he, as himself, really did give a speech that had nothing to do with the show, and people thought that was part of the show. So yes, it was a lot of art imitating life imitating art.”

4:02

Related

‘It’s an Aspirational, Slightly Hopeful Ending”: Robert De Niro and Eric Newman on That ‘Zero Day’ Finale

The legendary actor and showrunner get into the trenches of their eerie political thriller.

For Caplan, who stays off social media entirely, the show’s deep dive into political manipulation and the power of misinformation was more validation than revelation. “I thought it was terrible before; I think it’s terrible now,” she says flatly about social media’s role in shaping public opinion. While Zero Day highlights how quickly narratives can spiral out of control online, Caplan’s intentional distance from the digital fray has given her clarity about the whole situation. “I think people are really attached to it. I think that for many, many professions, it is now a mandatory component. It’s not for my job, so I opt out,” she explains. “Honestly, I don’t even see it as some big political statement. I think that if people really did opt out, they’d see, like, ‘Oh, you’re not actually missing that much by not being on it.’ You still waste a lot of time. Trust me, I still waste a lot of time without being on it.”
Lizzy Caplan on Sparring With Robert De Niro for ‘Zero Day’

“We shot that scene for an entire day…”

But while Caplan might sidestep the noise of social media in real life (and rightfully so), there was no avoiding the high-stakes intensity on set, especially when going toe-to-toe with De Niro in some of Zero Day’s most charged scenes. One of the series’ best moments comes from the heated argument between George and Alex in the finale where she pleads with her father, telling him why she played a part in the cyberattacks with Speaker of the House, Dryer (played by Matthew Modine). It was an emotionally charged moment that was expertly performed, but as Caplan admits, it wasn’t an easy shoot.
“We shot that scene for an entire day, so 12 hours. It was a very long day,” she says of the attention to detail for every moment they held space for one another. “A very exhausting day. We were messing around with different things while we were shooting it, which was great. I haven’t seen that episode, so I’m very, very, very pleased to hear that it cut together. For me, it was an exercise in trying to maintain that level of intensity for that many hours while also not losing sight of the fact that it was really fucking cool to be doing this with Robert De Niro.”
And yes, Caplan is aware her screen time with the iconic actor is a brag-worthy moment she’ll never let go of: “I’m gonna dine out on that forever. Trust me,” Caplan laughs.
Zero Day is now streaming on Netflix.

Zero Day

Release Date

2025 – 2024

Network

Netflix

Writers

Dee Johnson