Philadelphia, U.S.A. 1838. Like America, the Krieger companies are clawing their way back from the Panic of 1837. Fourteen-year-old Rian Krieger knows this because she starts every workday as her father's bookkeeper and the money is flowing in. When the accounting is up to date, Rian scoots to her real love: the production floor of Krieger Locomotive.
To Rian, idleness equals bad, but not in a "rich people are industrious and the poor are idle" sort of way. If Rian doesn't immerse herself in a task that demands total concentration-bookkeeping, drawing a new part for a locomotive, pouring molten iron into a mold, caulking a boiler-dark thoughts gnaw their way loose like rats escaping from a burlap bag. You are The Oddity: The girl who hates girly-girl things. The girl who wears boys' clothing. The girl who intends to run Krieger Locomotive someday. Then an exploding steam engine puts Rian's plan in jeopardy and makes way for a host of new rat-thoughts.
Rian's father, Otto, bets everything-factories, home, reputation-on his assumption that the railroad industry will lead America out of the depression. He has to be successful, for if he doesn't build a fortune, how else will his daughter marry well?
And in South Carolina, Olivia Tucker, the daughter of plantation owners, rebels against her destiny: a life of privilege built on the backs of the enslaved. Olivia enlists Rian in a long-distance conspiracy to burn the daily cruelties of the South's slave system into the American consciousness.