"Where are you? The dogs are here." It's the Discovery Channel PR handler, calling from the set in downtown Los Angeles.

"Stuck in traffic," I say. "These storms got everything backed up."

I've got to hurry—the dogs are about to attack!

It's a dreary day in early February, and I'm just barely crawling along the freeway, creeping past one ugly accident after another. The latest in a series of El Niño storms is turning the L.A. foothills to mud, and now whole neighborhoods are sliding into oblivion. Miles ahead, somewhere in downtown L.A., Bear Grylls, the 36-year-old former UK Special Forces paratrooper who for the past four years has braved the world's harshest environments as the star of the Discovery Channel's runaway hit Man vs. Wild, is about to be mauled by wild dogs as part of his latest foray into reality television—a new series, making its debut this spring, called Worst Case Scenario.

With the show, Grylls is essentially bringing the feel and concept of his fabulously popular Man vs. Wild and applying it to the city. Based on the perennially popular Worst Case Scenario books, survival manuals, and board games, he is presented with a number of classic hypothetical situations of high peril from which he then endeavors, with the help of advice from experts, to extricate himself. Over the past few days, he's demonstrated for the cameras what to do if you're in a free-falling elevator, if your car's brakes stop working on a steep hill, or if you're suddenly trapped inside a burning vehicle. I plan to watch the filming of an episode on what to do if a dog attacks, but I'm trapped here in this crappy rental car, growing ever more vexed by the screak of my wiper blades.

A half-hour later, I turn into a rain-soaked studio parking lot in an industrial warehouse district near the Los Angeles River and find Grylls's trailer, inhabited by a lonely line editor. "Wait here," she tells me. Listening to the drone of the generators, I spy his clothes, his flip-flops, a package of nuts: Bear tracks, but no Bear. Soon a black Yukon pulls up and transports me over to the set, which has been rigged up beneath the classic art deco 4th Street bridge. Tucked back from the spitting rain, the crew is filming an episode of Grylls's new show in an urban jungle of concrete pylons streaked with pigeon guano. The Discovery Channel, which ordinarily guards access to Grylls, has promised me an exclusive sneak peek on the set.

"There you are," the PR handler whispers, emerging from the bridge's gloom. "It's OK. The dogs are still here."