Series enumeration from goodreads.com.

"Georgie ... impatiently awaits the birth of her baby. But she has plenty to occupy her: her new chef Pierre has arrived from Paris, and Sir Hubert, who owns Eynsleigh, is back from his latest expedition. It's time for Georgie to throw her first house party to celebrate his return and show off her new chef. ... Sir Mortimer Mordred--famous author of creepy Gothic horror novels--is one of the guests. He recently purchased a nearby Elizabethan manor nearby because it has a famous poison garden. After the dinner, Sir Mortimer approaches Georgie and asks to borrow her new chef for his upcoming party. ... Shockingly, just after the banquet several of the guests become sick. And one dies, apparently poisoned by berries from the garden. But how could this be when they all ate the same meal and the same delectable dessert?"--