Gerri Brightwell's The Dark Lantern opens in London in 1893. Sixteen-year-old Jane Wilbred, an orphan whose mother was hanged after being convicted of murder, has forged a letter in order to obtain a position as second housemaid for the Bentley family. She left her job working for a heartless and domineering mistress and traveled for five hours by train, hoping that her new situation will be a step up for her. Little does this naïve creature realize that she is a fly about to be caught in a spider's intricate web. Jane will soon settle into an arduous and backbreaking routine. She will be exhausted from her daily grind of hard labor followed by a few hours of rest in a freezing room. She will have almost no time to herself and her hands will become red and raw from incessant scrubbing and cleaning.
The mistress of the Bentley household is an elderly woman who is lying on her deathbed. Her son, Robert, and his wife of four years, Mina, have left Paris to take care of matters during his mother's illness. Robert and Mina are almost penniless. They have been living on money that Mina inherited, but their funds are almost gone. Although he does not earn any income, Robert spends his time promoting anthropometry (the science of identifying criminals using body measurements), which he learned from the esteemed Monsieur Bertillon in France. Robert would like the English government to adopt this system, which he claims is superior to dactylography (fingerprinting) as a means of identification, but he has not yet convinced British officials that his method is both efficient and accurate.