The future looks bright for Charlotte Edgerton when she moves to bustling New York City in 1843. But when first one and then another of the glamorous "sporting girls" who work in the city's famous brothels is murdered, Charlotte becomes aware of the darkness that lurks behind the bright glow of Broadway. New York is living up to its nickname of Sin City. Shocked by the arrest of a colleague's husband for one of the deaths, Charlotte and her fellow immigrant Daniel Gallagher take on the challenge of unmasking the real murderer. Their quest leads them to popular theaters where they observe suspicious activities in the balcony, and to political rallies that threaten to turn into riots. They meet with poets and performers whose views of the city and the people who live and work there reflect their different backgrounds and experiences. While they struggle to unearth dark secrets hidden in the upper reaches of society as well as shabby side streets, Charlotte and Daniel fall more deeply in love. Defying the interference of bigoted policemen and corrupt politicians, the pair seek out the truth with the help of spirited sporting girls determined to take charge of their own lives and resist the demands of the unscrupulous men who try to control them. But when Charlotte attempts to rescue the child of one of the murdered women, she finds herself being pursued by a determined and conscienceless enemy. Will Charlotte be able to discover the source of the evil and end the terror gripping women throughout the city?