London, 1850. Meet Tommy. He’s five years old, and his job is climbing inside chimneys that are barely seven inches wide. His parents sold him to a master sweep for two pounds. They couldn’t afford to feed him. Every morning before dawn, Tommy climbs into flues that are still hot from yesterday’s fires. He scrapes soot with his elbows and knees. He can’t breathe. The soot fills his lungs, his eyes, his throat. If he gets stuck—and boys get stuck often—his master lights a fire below to force him to climb faster. Some boys suffocate. Some burn to death. Tommy’s knees and elbows are scraped raw, infected, covered in soot. The wounds never heal because he climbs again tomorrow. The soot causes cancer—“chimney sweep’s carcinoma.” Most sweeps develop it by their teens. Most are dead by twenty-five. Tommy died at twelve. This wasn’t abuse. It was legal. Normal. There were thousands of climbing boys across England. Some as young as four. Parliament debated banning it for decades. Factory owner...