On our way from Oregon to Vail, we stopped at every major store in every major city in three states. We stopped at every RadioShack. There are only so many, and we could get only so many components at each one without raising suspicions. We bought everything in cash and in small quantities. An alarm clock and maybe a bottle of water from a Fred Meyer. A box of matches from an Albertsons. A spool of wire from a hardware store. We always wore baseball caps to shield our faces from overhead cameras, just in case.

We stopped at a motel in Utah to assemble the timers for the incendiary devices. It was a nightmare. Avalon had instructions, but he'd never built this kind before. These timers were digital, with longer delays than the ones he'd used—delays long enough for us to get down off the mountain and out of the area before the fires started.

Who is Chelsea Gerlach?

Thirty-year-old Gerlach was part of the Earth Liberation Front cell best known for burning down the Two Elk Restaurant, at Colorado's Vail ski resort, on October 19, 1998. Between 1996 and 2001, Gerlach's group, operating mainly in the Pacific Northwest, torched lumber companies, wild-horse corrals, and genetic-engineering facilities—more than 20 arsons in all. In 2004, former ELF activist Jake Ferguson, who had become a target in the investigation, began wearing a wire for the FBI and recording incriminating conversations with his former colleagues. Gerlach was arrested in December 2005 in a sweep that also nabbed William Rodgers—whom she knew as Avalon—her boyfriend, Darren Thurston, her former boyfriend Stanislas Meyerhoff, and eventually ten more people. Later that month, Rodgers suffocated himself with a plastic bag in his cell. Others, including Gerlach, pleaded guilty, cooperating with the government in exchange for lighter sentences. On May 25, 2007, a judge gave her nine years in federal prison. For seven months, Gerlach has been writing answers to Outside's questions on lined paper provided by the Lane County jail, in Eugene, Oregon. After her sentencing, she sent them to writer McKenzie Funk, her classmate during high school in Eugene. Every night for two weeks, she called Funk collect from jail to follow up and explain what kinds of acts, in her mind, are ultimately defensible for the cause.

Half the clocks we bought didn't end up working with the design. We abandoned them altogether after we realized they wouldn't work in the cold.

Once we got to Vail, we tried to drive the fuel—some gas, some diesel—up the mountain one night, but there was too much snow, and my truck got stuck. We spent hours trying to dig it out. There were maybe 75 gallons of fuel in the back, it was starting to get light out, and there were hunters around. We stashed the fuel cans in the woods and got out of there. The fuel was still miles below our target, a string of buildings and ski lifts on a ridge at 11,000 feet; it would have to be hiked up the mountain. We drove a few hours away to meet some others who'd come out from Oregon to help. Now there were a half-dozen of us, but nothing was set. Most of the group just didn't believe it was possible, so they went back to Oregon. I wasn't really thinking that Avalon and I would end up doing it alone, but that's what happened.

I dropped Avalon where we'd hidden the fuel, and we set a meet time for a few days later—long enough for him to hike fuel can after fuel can several miles and hundreds of feet up the hill and hide them near each of the buildings. When I picked him up, he was exhausted. He rested for a few hours in the campsite I'd found way up a logging road, but there wasn't much time: The bulldozers were supposed to start rolling the next day. We finalized our plans, and I dropped him back at a trailhead in Vail. I returned to my camp and waited. The night of October 18 was cold, but I couldn't make a campfire—it might attract attention. I just stood in a forest of pines and firs and took everything in. I barely slept at all.