Sucking the blood, he inspected the sharp edge that had cut him. The fracture was in the barrel, one of the long straight sides of the link. He expected a ragged edge. What he saw was a surprise, and a mystery. Where the steel link had fractured was smooth and flat and sharp as a razor.

It looked like a piece had been cut out with a chisel. Using other links to tap it loose, he worked the broken link out of the one it had jammed in and put it in his pocket. Then he searched for the missing shackle. It must have fallen in the crosstie-lined trough between the steel rails of the coal train tracks.

He looked until his light began to run out of oil, but he never found the shackle. Another mystery. Obviously, the shackle had slipped out of the broken link. But how had the shackle separated from the thimble that formed the wire loop he had seen at the winch?

As he continued up the rails, out of the mine, he recalled the cops who’d been watching him. Rather than get caught with the broken link if they made him turn out his pockets, he slipped it into a crack between a prop and the coal seam and noted the spot carefully in his memory—four support props above the lowest side gallery.

He started up. Or was it three? He went back, counted again, touching each. Four. The hairs prickled on the back of his neck. He had a photographic memory. How could he forget a picture so simple as these four ceiling props standing in a row? He noticed a strange silence. Something had changed in the narrow passages. The ventilators had stopped blowing fresh air.

The damps were gathering again. No wonder he felt light-headed. Bell turned and stumbled upward, toward the distant mouth. If it was blackdamp, he hadn’t a prayer. The carbonic acid would stop him within seconds. White damp from the extinguished fire? Minutes. Less than ten.

He broke into a shambling run. His head was pounding and his heart hammered in his chest. He imagined the poison gases chasing after him, breaking like a tidal wave, cresting, splashing, clutching his boots, his knees, tugging at his legs, suction pulling him under. He ran harder, his fading light bouncing low shadows from the crossties. Two ties for each step. He made himself stretch for three longer strides, flowing over the floor of the mine faster than the wave crashing after him.

He was pulling ahead when he saw something gleam in his light. It was tucked against the right rail, half obscured by a wooden tie. He slowed, stopped, stared down at it, desperately trying to mine thoughts from a heavy head. The shackle? Did he imagine it? Or did he see a piece of it directly under his feet? Should he try to pick it up? He had the feeling that if he knelt to pick it up, he might never stand again. His head was spinning. But it was important. The saboteur . . . He gathered his strength and dropped to one knee. Before he could reach it, it disappeared in a shadow that moved over it.