In 'Warm Bodies,' a zombie has feelings Zombies are people too. Or they were, before they became the flesh-craving, brain-eating undead. The new film "Warm Bodies," opening Friday, is an unlikely hybrid of horror film and young adult romantic comedy that transforms a zombie apocalypse into a last stand for feelings. The film is based on the novel of the same name by Isaac Marion, adapted for the screen and directed by Jonathan Levine. Set in a future where many people have inexplicably turned to zombies, the story opens with a zombie narrator (Nicholas Hoult) who can only recall that his first name started with "R" and who feels increasingly dissatisfied with his undead lifestyle. Once R comes across still-living young Julie (Teresa Palmer), he makes the decision, mysterious at first even to himself, to not eat her but protect her, setting in motion a series of events that will potentially save mankind. "It was the book that kind of hooked me on the tone," Levine said of the unusual blend of horror, humor and romance in "Warm Bodies." The tone of the movie is like one click different from the tone of the book, but I really loved the idea of what it was doing with genre and how it was using not just the genre of the zombie but the genre of a romantic comedy. R, Levine added, is a "guy who was just like any other guy. His being a zombie is the same as me sitting down with a pretty girl and not being able to talk. He's just trapped in his own skin. "Warm Bodies" is the fourth feature directed by the 36-year-old Levine, a native New Yorker and graduate of the AFI Conservatory in Los Angeles. His previous films all unexpectedly crossed genres, with the horror thriller "All the Boys Love Mandy Lane," the light-hearted drama "The Wackness" and the cancer comedy "50/50." The zombie project began when Marion published a short story online and then expanded it into a novel. The then-still unpublished manuscript came to the attention of producer Bruna Papandrea, who in turn took it to executives at Summit Entertainment who were already in conversation with Levine. Things moved forward from there, with Levine attached when the film project was first announced in early 2010. He worked on the script while prepping to shoot "50/50," also for Summit. "Warm Bodies," which was made in the low-to-mid $30-million range, according to sources close to the production, was shot in Montreal, in part because a large chunk of the story takes place at an abandoned airport, a hard-to-find location that that city just happened to have. To nail down the film's unusual tone, Levine brought in writers Kyle Hunter and Ariel Shaffir, whom Levine met through "50/50" star Seth Rogen and Rogen's creative partner Evan Goldberg. They helped punch up the comedic counterpoint of the film's voice-over. Hunter and Shaffir are not credited but they are mentioned in the film's end-crawl thank yous. In both the novel and the movie, the zombie world serves as a mirror image of our modern reality, with people trudging through their daily lives, disconnected from one another. "If you try to imagine what a zombie might think in a post-apocalyptic world, it surprised me, the similarities to the idea of a detached, lifeless, apathetic person trying to come out of that and reconnect to being alive," said Marion. The novel was first published in 2010 to positive reviews and has steadily built an audience since then. This week, Marion released an ebook prequel to the story called "The New Hunger" and is at work on a sequel. A zombie movie means lots of rules of course - do they move fast or slow, how do they die, etc. - and Levine knew whatever decisions he made would upset someone somewhere protective of the zombie canon. "I was always picturing the message boards that were going to bitch about violations of the rules," said Levine. But I wanted those people to know that in the soul of the movie we cared about them, whatever their quibbles might be. The soul of the movie was from a fan's perspective. The movie's biggest twist on zombie lore came straight from Marion's novel: In the book, when a zombie eats someone's brain, he or she is hit by a wave of the victim's memories. In the story, part of what brings R back to life is his slow savoring of the brain of Julie's boyfriend, allowing him to experience afresh what it would be like to live and love. "I won't say it had never been done before, but in mainstream stories it had never been explained why zombies like eating brains," said Marion. Going into the perspective of the creature, imagining why I'd be doing the things I'm doing, it just seemed like the obvious answer to me that a creature with no memories and no identity would enjoy eating the brains of a living person. It would give them the things they lacked, memories and the experience of being alive. Summit does have some experience with supernatural youth romance pictures, having released the "Twilight" franchise. Whether "Warm Bodies" will step into the vacuum left by the end of that series and scoop up any of its ravenous audience remains to be seen. For all of its proto-emo earnestness, the film also has a streak of bracing self-awareness (such as when R remarks in the voice-over upon the hoodie he wears throughout, or when Julie holds up a DVD of Lucio Fulci's horror classic "Zombie.") "The film does poke fun at itself and takes itself lightly, but it can't become a parody and you do have to care and root for the characters," said Hoult, 23, who has gone from being the boy in "About a Boy" to appearing in the upcoming "X-Men" and "Mad Max" sequels as well as "Jack the Giant Slayer." For me it was about playing it straight and trying to believe it all. That sense of emotional reality amid a fantastical setting was key to bringing "Warm Bodies" to the screen. "When you talk about it, it sounds ridiculous - a zombie and human falling in love through the course of some comedy romance action adventure," said Todd Lieberman, a producer along with David Hoberman. But it's real, you believe it. And if we didn't have that, the movie wouldn't work at all. "When we tested it people said they found it believable, and I always wondered, what does that mean?" asked Levine. But they find the progression of the relationship believable. And that was always very consistently my compass in the movie: This is about a guy and a girl.