Summer has arrived at Hollyhock Cottage, and romance is in the air. The roses are about to bloom, the garden nursery is filled with fragrance and color—and Poppy is going on her first proper "date" in a long time. Despite her qualms about mixing business with pleasure, she's accepted an invitation to dinner from a charming pesticide salesman and is looking forward to a night of flirting and fun. Instead, the evening ends with a chilling murder—it seems that insects weren't the only ones who found her handsome date toxic company!

Now, the hunt is on for a clever killer with a deadly knowledge of poisons. Luckily, Poppy can count on her "mad scientist" neighbor Bertie to help her sort the cyanides from the cycads, and she soon finds that her sleepy English village is crawling with suspects. There are hostile colleagues with scores to settle and jilted ex-girlfriends with points to prove... but was the murder connected to the victim's job? Or was the motive more personal?

Meanwhile, Poppy is grappling with problems at the cottage garden, too, from mysterious pests attacking her roses to disgruntled customers leaving in droves—not to mention a runaway slug leading her on a merry chase! Then there's Oren, the cheeky ginger tomcat, poking his paws where they don't belong. But when a threatening note arrives, Poppy realizes that cats aren't the only ones killed by curiosity. Can she solve the mystery and live to prune another day?