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It's a helluva three-word pitch: "Zombie heist movie."

You can immediately envision a story about a capable hero who assembles a team of undesirables to infiltrate an impregnable fortress (in this case, a Las Vegas casino) during an undead uprising. Call it Ocean's 11 Days Later, or The Fast and the Cadaverous, or even its actual title, Army of the Dead. But according to writer-director Zack Snyder, there's one major element of his Netflix movie you won't see coming.

"It is a full-blown, balls-to-the-wall zombie heist movie, so it's genre-on-genre in a great way," says Snyder (Man of Steel, 300) in an exclusive first look behind the scenes of the film coming later this year. "So you expect pure zombie mayhem, and you get that, 100 percent. But also you get these really amazing characters on a fantastic journey. It's going to surprise people that there's a lot of warmth and real emotion with these great characters."

Yup. A zombie heist movie — but with heart!

Snyder got the idea for his monster genre mash-up shortly after finishing his acclaimed 2004 remake of George A. Romero's classic Dawn of the Dead. The new film's setup is that a plague has been released from Nevada's secretive Area 51 military base. The U.S. government has managed to contain the outbreak by building a wall around an overrun Sin City. But there's still all that cash in zombie-infested casinos, if only somebody is brave (or dumb) enough to try to go and get it.

"With Dawn, we made a zombie movie but tried to do it all the way with all of those tropes of the genre," Snyder says. "That was so fun, so I started to think of what were other genres that story didn't have room for. It's this tone where you have fun with the genre but you don't make fun of the genre — it's a fine line."

For years, the idea languished in development at Warner Bros. "They didn't want to spend that kind of money on a zombie movie, or just didn't take it that seriously," Snyder says. "I was always like, 'Look guys, this is more than [just a zombie movie],' but it fizzled out."

Then Netflix stepped up to stake the project, as the streamer tends to do. "We were in a meeting at Netflix and I was talking about some of these scripts I was working on," Snyder recalls. "And I mentioned the idea to [Netflix head of original films Scott Stuber] and he was like, 'That is the movie! Go write that movie and let's make it.' I was like, 'What, do you mean now?' And he's like, 'Go write it tomorrow and we'll do shoot it in a week.'"

Netflix was so enthusiastic about the idea, the streamer also funded a four-hour animated prequel series. The prequel will dive into the plague's origin story, which is another genre departure for the project as most zombie movies and TV shows tend to either keep the origin of the outbreak frustratingly vague (like The Walking Dead) or give devote only a single scene to the subject (like 28 Days Later). "I've done a very deep dive with the why of the zombie plague and where it starts," Snyder says. "Sufficed to say, that it does come from Area 51 -- that's in the film's opening scene – and then the whole cast is in the animated series, along with Christian Slater as the bad guy. We really do a super deep dive on where this like zombie plague came from."

Snyder doesn't want to reveal too much about the zombies themselves, but will say the film as "the normal shamblers" – Romero-style slow walkers – and also "another level of zombie."

For his lead hero, Snyder reached out to Dave Bautista (Guardians of the Galaxy), who quickly said the opposite of yes. "I said I wasn't interested," Bautista recalls. "I had this chip on my shoulder and was looking for juicy [dramatic roles]. Then I read the script and it was a lot deeper and had more layers than I thought. And also, to be quite frank, I wanted to work with Zack." Bautista became such a convert, he says he gave up a part in Guardians director James Gunn's upcoming The Suicide Squad to keep the role.

The project hit a far more serious snag after filming wrapped when a member of the ensemble cast, Chris D'Elia, was accused of sexual misconduct by several women in June. Snyder asked another actor from the stand-up world, Tig Notaro (Star Trek: Discovery), to play D'Elia's sarcastic helicopter-pilot character. "We just felt like the right thing to do," Snyder says. "It was the best thing to do not just for the property but for respecting humanity and people and decency. In the end, it was a pretty easy choice."

But the production shake-up meant putting Notaro in the surreal position of performing against a greenscreen while attempting to fit into a film that had already been shot. "It's a comedic role, and Zack said he wanted me to do exactly what I do — which is good because I always tell directors, 'Before you say anything, just keep in mind that I have no range,' " the deadpan comedian says. "But I did start to think, 'Wow, I'm starring in a movie!' Because it seemed like I was the focal point of everything."

There's also a dash of political overtones – metaphors about immigration, consumerism, and a jingoistic president. "There was a lot of stuff in the movie in regard to what was happening along the border," Snyder says. "And there's a line where the president says going to nuke the city of Las Vegas to end the zombie plague – that it's kind of patriotic to do it on the Fourth of July."

But don't worry, Army of the Dead is basically just trying to do for casinos what Romero did for shopping malls. "We're running around killing zombies on craps tables," Bautista says. "It's just a ton of fun."

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