What Time the Sexton's Spade Doth Rust

There's a new arrival at Buckshaw - Flavia de Luce's obnoxious cousin Undine.

Flavia reluctantly takes on the mentorship of her fellow orphan, who in her best moments shows some potential for trespassing and trickery. When Major Greyleigh, a former hangman, is found dead from a breakfast of poisonous mushrooms, suspicion falls on the de Luce family's longtime cook, Mrs. Mullet.

After all, didn't she pick the mushrooms and serve them to Greyleigh moments before his death?

Flavia knows her beloved Mrs. Mullet is innocent. Together with Dogger, estate gardener and partner-in-crime, and the odious Undine, she sets out to find the real killer and clear Mrs. Mullet's good name.

But following the case's twists and turns will lead her to a most surprising discovery - one with the power to upend her entire life...