TODAY'S SHOOT will take place four blocks from the ocean, in some dingy old buildings that set designers have made over as the Snug Harbor Motel. Van Holt, the 37-year-old who plays Butchie, is sitting outside his trailer dressed in character: filthy jeans, a crusty ball cap, and corduroy slippers patched with duct tape. Blond and blue-eyed, with square shoulders and a rugged jaw, he's every surfer girl's dream. In fact, he looks remarkably like Bodhi, the Swayze character in Point Break. But Van Holt, who grew up surfing Huntington Beach and can still hold his own in the water, says he loves the 1991 cult classic—but cringes about it too, especially the scene where Gary Busey, playing an FBI agent, jumps on his desk, tucks into a big-wave crouch, and hollers "Whoaaaa!"

"I wanted to strangle somebody," says Van Holt, laughing.

Best known for his role in 2001's Black Hawk Down, Van Holt says he felt "possessed" after first seeing a John from Cincinnati script. "This is my calling," he remembers thinking. "I am Butchie. I was meant to be Butchie." Van Holt craved an audition. But when casting began in June 2006, he was about to leave on a surf trip to Indonesia; he'd be living on a chartered boat for two weeks, moving from one reef break to the next. The boat did have a fax machine, and a few days into the trip a fax arrived, offering him an audition the next day. "I'm in the fucking Indian Ocean," says Van Holt. "I drank my sorrows away."

Yet in sync with the mystical, what's-meant-to-be-will-be vibe that pervades the show, the role was still open when Van Holt returned to the States. He read for Milch and won the part. Like most everyone on the John from Cincinnati set, Van Holt struggles to explain the series to the uninitiated. "It's not about surfing," he says. "Surfing is the door you walk through to get to the story."

The most perplexing character on the show, and the one that audiences likely will have the most trouble embracing, is John himself. Played by the 27-year-old Nichols, who starred in the 2006 movie Glory Road, John is what Steve Hawk, the former editor of Surfer magazine whom Milch has hired as a scriptwriter, calls a "transmitter"—a seemingly naive young man controlled by something more mystical than sci-fi. A clue to what Milch was thinking when he created the character lies in John's last name: Monad.

Monads, the German philosopher Gottfried Leibniz wrote in his 1714 treatise Monadology, represent the fundamental unit, "the true atoms," of the spiritual world:

God, in ordering the whole, has had regard to every part and in particular to each monad; and since the monad is by its very nature representative, nothing can limit it to represent merely a part of things. It is nevertheless true that this representation is, as regards the details of the whole universe, only a confused representation ... If the representation were distinct as to the details of the entire Universe, each monad would be a Deity.

Um, OK.

"John purifies intentions," Milch tells me at one point, likening the character to a mirror others can peer into and see themselves. "If I could explain it fully, I wouldn't have to tell this story."