Last year, Alan Bradley made a splash in the mystery world with The Sweetness at the Bottom of the Pie, which introduced 11-year-old Flavia de Luce, one of the most original and charming sleuths to appear in recent memory. Flavia spends her time concocting noxious substances in the makeshift basement laboratory of her family’s home in a quiet English village, tormenting (and being tormented by) her older sisters Ophelia and Daphne, and doing her best to be a dutiful daughter to her somewhat absent-minded widower father. Suffice to say Flavia is a great deal wiser than her 11 years, though her maturity seems appropriate for the early 1950s time frame.

As Sweetness demonstrated, Flavia is also a sharp-witted amateur detective, able to skilfully deduce who laced a freshly baked pie with poison. The novel’s success, however, owed less to its plot than to Flavia’s acerbic, first-person voice, and to a newfound resurgence in classical mystery stories that have been tweaked for a 21st-century readership.

Bradley marshals these elements for the  equally delightful sequel, the first page of which finds Flavia “lying dead in the churchyard.” As the precocious youngster plays at being a corpse, she makes macabre references to her own gravestone and the imagined reactions of her family members to her untimely demise. Flavia’s fun is spoiled when she stumbles upon a woman “stretched out full length, facedown on the slab of a limestone tomb, her red hair flowing out across the weathered inscription like rivulets of blood.” The only evidence that the woman is alive comes from “the cigarette wedged stylishly erect between her fingers.”

The ginger-haired lady is Nialla, assistant to the diminutive yet somehow larger-than-life Rupert Porson, the brains behind England’s most famous children’s show, The Magic Kingdom. Porson has agreed to put on a live performance of Porson’s Puppets, his travelling puppet show, at the parish hall. He takes a shine to Flavia and recruits her as his second assistant in the run-up to the performance.

It should come as no surprise that murder soon intrudes, and that Flavia gets mixed up in the whole thing, leading to an Agatha Christie-esque climax in which all the suspects are gathered round so that the young detective can unmask the culprit (once certain suspicions are confirmed and theories proven, of course).

Well before that, however, Bradley – by way of Flavia’s caustic, unwittingly winsome narrative voice – offers some nifty portraits of the story’s supporting players. For example, Cynthia Richardson, the vicar’s wife, acts the very essence of propriety, but, in Flavia’s estimation, can’t quite pull it off: “By all reports, she was a saint, a tiger, a beacon of hope to the sick, and a comfort to the bereaved. Her good works were legendary.… And yet.… There was something about her posture that just didn’t ring true: a horrid slackness, a kind of limp and tired defeat that might be seen in the faces and bodies of Blitz victims in the wartime issues of the Picture Post. But in a vicar’s wife…?”

Or take Felicity, Flavia’s visiting aunt, a force of nature who terrifies the seemingly unflappable sleuth-in-training with regular edicts to “carry on the glorious name of de Luce.” What Felicity means by this is very clear: “You must never be deflected by unpleasantness.… Even when it leads to murder.” Ophelia and Daphne, who spend much time disapproving of Flavia’s “unhealthy fascination with death” are no match for such conviction, and those who dare to underestimate the steely determination and analytical precision of the tough pre-pubescent detective do so at their own peril.

The Weed That Strings the Hangman’s Bag works more as an outright sequel to the earlier book than as a stand-alone novel, so readers new to the series may need to consult the previous novel to get up to speed on Flavia’s family dynamics and love of all things poisonous. Once they do, however, they will find themselves catapulted into Bradley’s vividly drawn simulacrum of a small English village, and his crisp depiction of intruders from the big city who act as catalysts to uncover the festering rot lurking beneath seemingly close-knit relationships.

The secret of the novel’s charm involves the way in which Flavia teeters on the border between precocity and childishness, spouting faux-cynical epithets that result from the fact that her intellectual gifts far outpace her emotional capacity. The bittersweet flavour that’s hidden in the mix of The Weed That Strings the Hangman’s Bag – and which will perhaps develop over the course of later books – arises from the realization that as Flavia reaches intellectual and emotional equilibrium, her sleuthing ability may plateau as well.

And so, we have a potential dilemma: will Flavia remain forever on the cusp of womanhood and expected domesticity, a proto-pioneer in matters toxicological? After two books, this is a mystery readers will be eager to solve.