“We need manpower to track down those torpedoes. He’s got to convince the Navy, Coast Guard, and the police Harbor Squads in every city with a battleship yard—Camden, Philadelphia; Quincy, Fore River, Massachusetts; Bath Iron Works, Maine; Brooklyn—that the threat is deadly. Then I’m going repeat what I’ve been telling him all along. This is, first and foremost, a murder case. It will take old-fashioned detective work to hang Eyes O’Shay. We’ll start with Billy Collins.”

ISAAC BELL LEFT the Hotel Knickerbocker by the kitchen door. He dipped his fingers in a vat of used beef fat waiting to be picked up by the rendering plant and rubbed it into his hair. In the alley, down-on-their-luck men were waiting on the breadline. He astonished one, who despaired of raising a nickel to flop indoors on this chilly night that threatened rain, by offering five dollars for his battered slouch hat. Offered the same amount, a man almost as tall as the detective parted eagerly with his ragged coat.

Bell palmed a rusty revolver with three slugs in it and shifted it from his trousers into the coat. He pulled the hat low over his brow, worked his golden hair under it, and buttoned the coat to his chin. Then he shoved his hands in his pockets, bowed his head, and stepped out of the alley onto Broadway. A cop told him to move along.

For the fifth time in five days, he wandered Hell’s Kitchen.

He was learning its rhythms, where and when the slum blocks were busy, the streets rumbling with wagons and trucks, the sidewalks crowded, as men streamed into saloons, women into churches, and children roamed, ignoring mothers shouting from tenement windows. He had previously wandered from Ninth Avenue to the river and from the Pennsylvania Railroad Station construction site at 33rd to the 60th Street rail yards. But he hadn’t found the “hop fiend,” Billy Collins, who might lead him to Eyes O’Shay.

So today Isaac Bell was taking a different tack.

As part of his disguise, he limped, left foot dragging slightly, scuffing the shine off his boots as he crossed curbs and streetcar tracks. A coal truck backing to a cellar chute blocked the sidewalk. Bell trailed his fingers along its sooty side and stroked his mustache. He repeated the exercise when he passed an ash can, still warm, and ran his fingers through the hair that escaped from the slouch hat. He inspected his reflection in a window. His eyes glittered too brightly in a worn face. He cast his gaze downward, plucked a clump of straw out of the gutter, and rubbed it to his sleeves until it appeared that he had slept in his coat. They never look a dirty man in the face, Scully taught the apprentices.