Eighteen-year-old Angélique dreams of designing extravagant gowns like the ladies in the bourgeoise wear to balls and soirées. Because she's working-class, Angélique knows that her life will, instead, be spent dyeing silk for a living. That is, until her parents and younger sibling are killed in the sweatshop where they've toiled. Now orphaned, and with another sister to protect, Angélique vows vengeance against the factory owner growing richer by treating his employees as disposable.

To improve her station, Angélique takes a position as a junior seamstress for Paris's top modiste. Though she's bullied for being poor and her meager salary isn't enough to pay rent, she refuses to give in. Her sister and crush, a handsome, immigrant shoemaker, won't allow it. Then the modiste proposes a contest to win the well-paid, coveted assistant position. Angélique would do anything to earn the career of her dreams. What's a little arsenic between girls after all?

As Angélique outshines--and outlives--the competition, she also wields her newfound privilege and power to exact revenge on those who ruined her family and blossoms into a new role: Paris's greatest protégée.