Cassandra Nottingham, the noted garden writer, is suffering from the winter doldrums. So when Oliver Dickens, the owner of an antiquarian Victorian book store, asks her to give a series of evening garden lectures Cass reluctantly agrees. As soon as she meets the participants her misgivings rise to despair. Few of them know anything about gardening. The only enticement is the book store's tea room where the chef, surly Norman Tringle, serves delicious pastries and lunches. At the second lecture, just as Cass is ready to throw in the towel, someone using a highly unusual weapon murders one of the participants. Cass rushes into the search for the murderer as she finds herself pitted against a seven-foot policeman who tries to thwart her at every turn, as well as the other participants who have their own motives for taking the class, none of which have anything to do with Victorian gardening. Increasingly frustrated by the winter Puget Sound rains and Detective Inspector Thrupp, Cass races against the clock to uncover a diabolical plot designed to result in a second murder.