Adrienne Barbeau wasn't fully prepared when she auditioned for the HBO series "Carnivale."

"When I went in, I had only seen the sides," she says, referring to the short scenes actors read during auditions. "And no one had told me it was set in the '30s. I was reading it as contemporary."

Barbeau, no stranger to offbeat projects in a career that includes "Escape from New York" and "Swamp Thing," didn't see a full script until after she'd been offered the job of Ruthie, the snake charmer in a mystical traveling carnival in the Dust Bowl era.

"I was driving, and I actually started to read it while I was driving," she recalled Tuesday (March 16) at the Museum of Television and Radio's William S. Paley Festival. "I had to pull over to the side of the road and finish reading it."

Once she did read it, Barbeau -- along with the rest of the cast and, subsequently, a cadre of loyal fans -- was drawn into the world "Carnivale" creator Daniel Knauf had set up. In the bleak landscape of the Depression, Knauf hints at a coming struggle between good and evil, represented (we think) by Ben Hawkins (Nick Stahl), a drifter with the power to heal who latches on to the traveling carnival, and Brother Justin (Clancy Brown), a fundamentalist preacher in California's Central Valley, the promised land for many Dust Bowl migrants.

The setting appealed to Knauf because "As a writer, you're always looking for a patch of untilled soil."

"The Depression is such a pivotal time in U.S. history," he says. "So much was happening it seems almost a reasonable proposition that the devil was there."

Once it went into production, Knauf and the rest of the "Carnivale" crew took pains to depict the era and the lives of its characters as accurately as possible. When he started work on the script, though, Knauf was going on little more than what he'd seen at present-day fairs and carnivals.

"When you go to one of these things, and you see a face that looks likes it's been across the country and back -- and it probably has -- you just see a story there," he says.

As it turned out, much of the physical detail he originally saw in the imagined world of the show was fairly accurate to the way things were. For that, Knauf offers up an explanation that seems logical by "Carnivale" standards.

"Maybe," he says, "I was a carny in a past life."