This first instalment in an exciting new historical-fiction series by Marthe Jocelyn (Mable Riley; What We Hide) promises to woo a new generation of mystery fans.

In the character of Aggie Morton, Jocelyn’s created a fictional version of crime writer Agatha Christie as a child. The inquisitive 12-year-old is known for her “morbid preoccupation” and habit of daydreaming in eerie metaphors and similes. Aggie stumbles upon a startling crime scene at her dance class, which sets in motion a zippy, almost farcical story of mayhem, complete with rapid-fire plot twists and a quirky cast of characters. Along with her new Belgian friend and confidante, Hector Perot, Aggie tracks down clues to the shocking murder of the ornery town pill, Irma Eversham.

Employing authentic British colloquialisms and charming turns of phrase, Jocelyn’s writing has a bouncy rhythm that makes the story hum along. The author is adept at revealing tween complexities, taking her character through a wide emotional range. Aggie steels herself when facing terrifying situations like finding a dead body and being trapped by the killer. Her dance-recital stage fright is described as “icy cold and burning hot in alternating shivers.” And, as Aggie grapples with her father’s and grandfather’s deaths, she describes how “a fine, sharp needle twisted itself into my heart.”

Isabelle Follath’s portrait gallery provides an entertaining visual introduction to a large cast of shifty-eyed individuals and her illustrations open each chapter with a visual clue about what comes next.

Though mentions of “newsies” and “petticoats” may seem oldfangled, the book’s themes of women’s rights and immigration remain pointedly relevant. Suspicious townsfolk are encouraged to welcome Belgian immigrants at the “Befriend the Foreigners” event and suffragettes are starting to agitate. When Aggie expresses interest in becoming a lawyer, she’s told that the bar exams are “far too difficult” for girls and a female newspaper reporter is revealed to be posing as a man in search of better assignments.

If, as Agatha Christie said, “very few of us are what we seem,” then Aggie Morton can be counted on to reveal the truth – to the delight of middle-grade readers.