David Sweat pushed the teeth of his last remaining bit of hacksaw blade through the inner wall of the metal steam pipe. Weeks of working from inside the dark, dank cylinder had now come down to this one final cut. Drawing his knees in, he pressed the soles of his boots against the rectangular section he had chiseled. The fiberglass lining cracked under his feet. Within minutes, that part of the channel gave way.

Spring weather had brought the kind of luck Sweat needed. Clinton had shut down its heating system for the season, and the pipe — its surface scalding during the winter months — had started to cool. By May he was able to make his first incision. Using only the hook of his hacksaw blade he carved a tiny hole into its surface. He hewed away at the metal until the gap grew large enough to fit a grown man. Satisfied with the product, he crawled into the pipe, and approximately twelve feet down he began to whittle an exit. He normally would have used a drill for this work, but he could not risk the clang of power tools. Instead, he wore the metal away one inch an hour. Minutes turned to days, days turned to weeks, but Sweat did not care. He had nothing but time.

Now, tearing through some of the remaining insulation, he edged his way out of the pipe and stood fully upright in a long tunnel, which was dim and damp from years of exposure to contained steam. The underpass — used by Clinton contractors to access the piping system — was below Barker Street, a two-block residential road in Dannemora sprinkled with manholes. (Sweat did not know the street by name, but he knew that there was a paved road directly above the pipe.) He walked the length of the passageway, inspecting each of the exit points above his head. The first two had been chained shut, so he continued toward the end of tunnel to the last manhole, which opened with minimal effort.

Sweat peered out and saw a clearing behind the prison's powerhouse; the structure was an indication that he had gone too far. The last thing he wanted was to pop out of the ground into someone's front lawn.

He then backtracked about two hundred yards until he arrived at one of the other manholes. The plate was secured by chain, yet Sweat was able to sever a link using what blade he had left. Placing his palms flat on the surface, he extended his arms upward, heaving the cover onto the asphalt. He then climbed the iron ladder and lifted his head just above the lip. To the south was the powerhouse. To the north was the concrete perimeter wall.

He breathed in the free air of the Adirondacks.

"This will be perfect," he thought.

Sweat glanced at the silver watch that hung from a shoelace around his neck, its hands illuminated by a small LED light: 4:15 a.m. This was the latest he had been out since beginning work on the route — and he needed to be back on the block before the guards noticed his absence.

Even with little sleep, a sense of speed swept over him. He returned the metal cover to its proper position, sprinted down the tunnel, slid back through the steam pipe, and clambered out the other side. He then bolted toward the brick wall, removing those mortared blocks he had loosened weeks before, and scrambled through. Climbing the ladder to the catwalks, he crawled into the hole he had cut in the back wall of his cell on Clinton's Honor Block, and breathed a sigh of relief.

He checked his watch again: 4:27 a.m. Twelve minutes from start to finish, his fastest time yet.

Sweat turned to his tiny quarters. Among the towels, pillow cases, sweatshirts, and a few other miscellaneous items (a yellow Whitman's Sampler box and a Riverside Webster's II Dictionary, a paperback published in 1996 that boasted, "The Essential Reference for Successful Students") he pulled out a single Black and Mild, which he had stowed away for this very occasion.

He lit the end, grabbed a small handheld mirror, and held it through the bars of his cell so that his neighbor could see his reflection.

He tapped lightly against the wall.

"Matt! Matt, get up!"

Richard Matt groaned as he rose to his feet. He peered out of his own set of bars to see Sweat's dirtied face in the looking glass. The cigar hung loosely between Sweat's lips, which, even with the smoke between his teeth, spread into a wide, satisfied grin.

"Oh my God!" Matt said. "I can't believe it! No way! I can't believe you did it!"

A celebratory stogie was part of a pact they had made during the six months of preparations. It meant the route was ready.

Sweat passed a cigar to Matt, then quickly placed a basin of water onto the hotplate in his cell. It was well past 4:30 a.m., and he needed to wash off the evidence of the overnight outing before Clinton's guards conducted standing count. As he put on a clean pair of pants and scrubbed the callouses on his palms, now toughened from the self-appointed graveyard shift, he gave Matt explicit instructions to pass on to the prison seamstress, Joyce Mitchell: she was to be in the car this evening, parked near the powerhouse, her cell phone pressed to her ear, pretending to make a call. At 12 a.m. — exactly 12 a.m., as he had always been a stickler for punctuality — he and Matt would emerge from the manhole near the corner of Barker and Bouck Streets by the old Dannemora school building and make for her vehicle.

Sweat scribbled the orders down on a sheet of paper and handed it to Matt to give to Joyce. The plan was clear: today would be their last behind barbed wire.

Fifty-five miles west of Clinton in Dickinson Center, an alarm clock rang. As Joyce Mitchell reached through the darkness to shut it off, she remembered it was Friday, the day of the week she had come to dread. She did not know yet which Friday they would carry out their plan, but she knew one thing: Matt was telling the truth when he said they were making headway on the route.

For the last six months, the fifty-one-year-old prison seamstress had dreamed of a different life from the one she was living with her husband, Lyle. Since the couple had moved into the two-story house with the rusted metal roof on Palmer Road, an extra layer of heft had settled around her waist, and the corners of her mouth had given way to gravity. Her layered, outdated 'do — its individual strands as kinked as those on the ears of a spaniel — had acquired several variations of yellow over the years, and few cosmetics had ever found a permanent place in her morning routine.

On this morning, she got dressed, brewed coffee, and packed a lunch, as always. Joyce rarely ate before leaving; it was much more pleasant to have her breakfast — today, meat and potatoes, seared and roasted the night before — while seated at her desk in Clinton's Tailor Shop 1, where she could enjoy half an hour of stillness until 8 a.m. when the inmates arrived.

In the eight years she had been employed at the facility, Joyce — whom the prisoners knew as "Tillie," her longtime nickname dating back to her high school years — had come to welcome their company. She especially liked the company of David Sweat, whom she considered the most talented worker among the men she supervised. Joyce had openly admired his proficiency with patterns and skill with a sewing machine. (He could complete thirty to forty pairs of women's prison pants...