When the shadowy circumstances of a relative's death are brought to light, Jane and Lila are plunged into the recesses of an underground drug operation with links to a burgeoning fascist movement.

The Pool sisters have gone into business together: a down-home, if unequal, PI enterprise. But then Lila receives a shocking piece of news from an old friend of their Aunt Ruth's: their aunt's suicide more than a decade earlier might not have been what it seemed. A lawyer, she had represented a disgraced chemist working on a dangerous synthetic opioid. But once the client, Travis Nutt, was poised to lose, he went rogue and unleashed the adulterant as a street drug, in conjunction with a shadowy cartel. Can the twins solve the mystery of their aunt's death and bring this cultlike billionaire to justice?

Meanwhile, Jane has been invited to attend a writers' conference, an outlet she relishes until her dangerously confessional prose is seen by the wrong eyes. Her teenage daughter, Chloe, becomes the victim of a deepfake video while campaigning for class president and aggressively pursues the instigators, unaware of the muscle behind them. And old Harry, Jane's father, has stumbled upon a piece of unknown history that opens an unexpected door.

Buzz Kill is a rambunctious, kinetic, elastically braided narrative of a ride that shows J. Robert Lennon is at the height of his powers.