The Marmalade Murders is the ninth book in Elizabeth J. Duncan's award-winning mystery series, celebrated for its small-town charm and picturesque Welsh setting and starring amateur sleuth Penny Brannigan.

The competition is friendly and just a little fierce at the annual Llanelen agricultural show as town and country folk gather for the outdoor judging of farm animals and indoor judging of cakes, pies, pastries, chutneys, jams and jellies, along with vegetables, fruit and flowers. But this year, there’s a new show category: murder.

Local artist, Spa owner, and amateur sleuth Penny Brannigan agrees to help with the intake of the domestic arts entries and to judge the children’s pet competition on show day. When the president of the Welsh Women's Guild isn’t on hand to see her granddaughter and pet pug win a prize, the family becomes concerned. When a carrot cake entered in the competition goes missing, something is clearly amiss.

A black Labrador Retriever belonging to the agricultural show’s president discovers the body of the missing woman under the baked goods table. A newcomer to town, a transgender woman, is suspected, but amateur sleuth Penny Brannigan believes her to be innocent. She sets out to find the real killer, but when a second body is discovered days later, the case is thrown into confusion, and Penny knows it’s up to her to figure out what happened—and why.