Girl In Disguise by Greer MacAllister

In the tumultuous years of the Civil War, the streets of Chicago offer a woman mostly danger and ruin―unless that woman is Kate Warne. As an undercover Pinkerton detective, Kate is able to infiltrate the seedy side of the city in disguises that her fellow spies just can't manage. She's a seductress, an exotic foreign medium, a rich train passenger―all depending on the day and the robber, thief, or murderer she's been assigned to nab.

But is it only her detective work that makes her a daring spy and a clever liar? Or is the real disguise the good girl she always thought she was? As the Civil War marches closer, Kate takes on her most pressing job ever. The nation's future is at risk, and she's no longer sure where her disguise ends and the very real danger begins.

With magnificent historical detail, Girl in Disguise brings the adventures of one turn-of-the-century woman to tense, page-turning life.

Also by Greer Macallister:

The Magician's Lie

Woman 99