A 2026 LIBRARIAN FAVORITE, Children’s Book Council

After high school graduation, Piper Sail isn’t quite sure what her future holds—until a possible murder case lands in her lap. Filled with both the glitz and glamor of high society and the dark mafia underbelly of 1920s Chicago, The Secret Investigator of Astor Street is perfect for fans of Agatha Christie and Maureen Johnson.

Piper Sail knows what she wants: to become a detective. After all, she already solved the case of her missing best friend, and there’s no shortage of crime in 1920s Chicago. But for an eighteen-year-old society girl—even one who’s currently dating a police investigator—it simply isn’t done.

That is, until a girl asks her to dig into her brother’s recent death. The police ruled it a suicide, but she's convinced it was murder. And she wants Piper to help her prove it.

In this companion to The Lost Girl of Astor Street, Piper once again grabs her notebook and plunges into the underworld of mafia-controlled Chicago. But she’ll need all her wits and courage if she wants to become The Secret Investigator of Astor Street.