Daring Brooklyn detective Mary Handley teams up with Teddy Roosevelt to solve her husband's murder, only to run afoul of 19th-century New York's elite when she uncovers a dangerous conspiracy.

It's December 1896, and detective Mary Handley has done the last thing anyone expected of her: settled down. After falling in love with muckraking reporter Harper Lloyd, she turns her focus from pursuing new cases to raising her daughter Josephine. Little does she know her new-found happiness isn't fated to last--and neither is her break from policework.

When her husband turns up dead while pursuing a big story, Mary knows her next case must be solving his death. Harper was working on a big story--did it get him killed? As she sets out to solve his murder, she soon discovers that the case goes all the way to the top and may even involve some of wealthiest members of New York society, including the playwright W.S. Gilbert, the actress Faye Templeton, the architect Stanford White, and philanthropist Andrew Carnegie.

Realizing she's outgunned and desperate for justice, Mary turns to the one person who might be able to help: Commissioner Teddy Roosevelt. But as the two dig deep into the seedy underbelly of New York's social scene, they uncover a sinister conspiracy built around exploiting the city's most vulnerable citizens.