"When the blind little girl walked out of the ring with the city's most feared attack dog, the mob boss realized too late that he had just given away his ultimate weapon.

By five in the morning, the rain had returned as a light grey fog that hung three feet off the mud of the river road.

The horse—a twenty-year-old grey mare that Gidley had stolen from the Union Elevator’s dray barn thirty years ago and never returned—moved at a steady, rhythmic walk, her iron-hooped rubber shoes silent in the deep slush of the embankment.

Behind her, the small wooden spring-wagon rattled softly.

Inside the wagon box sat Marcus, Carrie, and Raleigh. The dog was covered by a heavy piece of tarred canvas that smelled of fish oil and coal grease, but his black muzzle protruded from beneath the hem, his dark nostrils drinking in the damp river air.

Gidley sat on the high bench, his hat pulled down over his single eye, his wooden leg braced against the footboard to keep his weight off his bad hip.

To their left, sixty feet down the steep shale bank, the Chicago River ran black and greasy between two lines of rotting timber pilings. The water didn't ripple; it slid toward the lake like cold lard being pushed through a pipe.

"There she is," Gidley said, pointing with his whip handle toward a low grey silhouette anchored two hundred yards off the grain docks.

It was The Mary Ellen.

She was a forty-foot wooden tug with a high wheelhouse and a short, fat funnel that was currently spouting thick, grey-black clouds of greasy smoke into the low fog. She wasn't moving. She was listing three degrees to port, her stern caught in the mud-bank near the old waterworks intake.

On her forward deck, three men were standing around the hatch cover, one of them swinging a heavy iron sledgehammer against the copper housing of the fuel pump.

The sound of the sledge—CLANG... CLANG... CLANG—came across the grey water with remarkable clarity, echoing off the high brick walls of the cold-storage warehouses on the far bank.

"They're choked," Marcus said, leaning forward over the wagon seat. "The sand’s in the injectors."

"It’s in the valves by now," Gidley said without turning around. "You can't burn river sand in a three-cylinder engine without turning the bronze seats into grit."

On the deck of the tug, a figure in a tailored wool coat stepped out of the wheelhouse.

Even at two hundred yards, through the fog, there was no mistaking Sean. He carried a heavy leather satchel in his left hand, his right hand jammed into his coat pocket where his fifth ring—the one with the horn setting—would be resting against his palm.

He looked toward the river road.

He couldn't see the wagon clearly through the grey mist, but he could hear the rubber shoes of the mare on the damp shale.

He raised his left hand. Something glinted in his palm—a small silver cylinder that caught the low light of the rising sun.

"He’s got a whistle, too," Marcus said, his voice dropping an octave.

"It’s an iron whistle," Carrie said from under the canvas. She hadn't lifted her head. Her hands were buried deep in Raleigh’s thick fur near his ribs. "The kind they use for the dogs in the pit. It makes a high noise that hurts his ears."

On the tug, Sean raised the silver whistle to his lips.

A long, thin, piercing screech split the morning quiet—a sound like steam escaping through a pinhole in a brass boiler. It was a sound designed to make a dog go mad with pain, to make him bite anything within three feet of his muzzle.

In the wagon box, Raleigh’s body went completely rigid. His ears laid back flat against his skull until his broad head looked like an iron wedge. His lips pulled back, revealing his long, yellowed canines and the dark pink roof of his mouth.

A sound started deep in his chest—not a bark, but a low, vibrating hum like an electric motor under too much load.

"Hold him, Carrie!" Marcus yelled, reaching for the nylon strap around the dog’s neck.

"Don't touch him," Carrie said softly.

She reached up with her left hand, found her father’s small cedar block, and placed it between her lips.

She didn't blow a sharp note. She didn't try to drown out the iron whistle across the water.

She blew a single, long, falling tone—a sound that rose three inches into the damp fog and then dissolved into the sound of the river water lapping against the timber pilings.

It was the tone a father uses when he’s bringing his horse through a deep creek at night—a sound that says the bottom is solid, the water is shallow, and there is no ice under the bank.

Raleigh’s ears flicked forward.

The red light in his yellow eyes cleared, replaced by that same terrifying, absolute calm that had filled the arena twelve hours before.

He didn't jump from the wagon. He didn't growl.

He simply stood up under the tarred canvas, lifted his broad black head toward the grey tug, and let out a single, deep, resonant bark that sounded like an iron church bell striking once in an empty valley.