It's 1907 Los Angeles. Mischievous socialite Anna Blanc is the kind of young woman who devours purloined crime novels--but must disguise them behind covers of more domestically-appropriate reading. She could match wits with Sherlock Holmes, but in her world women are not allowed to hunt criminals.

Determined to break free of the era's rigid social roles, Anna buys off the chaperone assigned by her domineering father and, using an alias, takes a job as a police matron with the Los Angeles Police Department. There she discovers a string of brothel murders, which the cops are unwilling to...