ISAAC BELL SAW THE ACROBAT JUMP ONTO THE cylinder rod that connected the piston to the drive wheels of the helper engine, and he saw the shadow of a trainman who tried to stop him fall to the ground. For a second, Bell thought the Acrobat himself was falling off. Instead, his arm shot up in a peculiar overhead motion. Suddenly he appeared to fly from the connecting rod up past the wheel fender to a handrail above it. He gripped the rail and flipped backwards. The simian silhouette blurred the stars atop the big helper engine, and then he was gone, disappearing like smoke.

Bell scrambled after him. The locomotive was festooned with handholds and steps so workmen could reach every part that had to be oiled, greased, cleaned, and adjusted. The fender above the Pacific’s seven-foot-high drive wheels formed a ledge alongside the boiler. He jumped onto the connecting rod, hauled himself on the ledge, stood up, and reached for the handrail. Only after he had locked both hands on it and was clenching his arms to pull himself up did he see the shadow of a boot cannonballing at his face. The Acrobat had not fled, but was waiting on top.

Bell whipped his head back and sideways, as if slipping a punch.

The boot whizzed past his ear and smashed into his shoulder. The Acrobat wore boots with india rubber soles and heels, Bell realized. A kick that hard with leather soles would have shattered bone.

The impact threw him off the locomotive. He fell backwards, tucking into a ball to protect his head. Tucking, twisting, he fought to regain his equilibrium in the air. If he could somehow land on the steeply angled side of the track bed instead of the flat top, he might survive the fall. The star-speckled sky spun circles like a black-and-white kaleidoscope. The dark ground rushed at his face. He hit the lip between flat and slope and skidded down the slope into a dry ditch.

Bell sprawled there, the stars still spinning. He heard a drumming noise, like hoofbeats. He wondered if he had cracked his skull again. But he hadn’t. His head, in fact, was about the only part of him that wasn’t going to hurt for a week. Scrambling to his feet, ignoring sharp pains in his shoulders and both knees, he heard the sound fade in the distance. Hoofbeats, of course. He had seen horses in starlight. And horses were the fastest way out of rough country.

He climbed up the embankment and came face-to-face with Clyde Lynds.

“Are you O.K., Mr. Bell?”

“I told you to stay inside and lock the door.”

“They’re gone. They rode away on horses.”

“Happen to catch a look at any faces?”

“No. But… Uh…”

“But what?” Bell demanded sharply, hoping for some clue.