It's been five years since the Sweep disappeared. Orphaned and alone, Nan Sparrow had no other choice but to work for a ruthless chimney sweep named Wilkie Crudd. She spends her days sweeping out chimneys. The job is dangerous and thankless, but with her wits and will, Nan has managed to beat the deadly odds time and time again.

When Nan gets stuck in a chimney fire, she fears the end has come. Instead, she wakes to find herself unharmed in an abandoned attic. And she is not alone. Huddled in the corner is a mysterious creature―a golem―made from soot and ash.