Lina's uncle died as a seemingly poor man. However, it turns out that he left her and two other heirs a task, promising a small fortune to whoever can solve a case that derailed the uncle's life thirty years ago. Three amateur detectives search for the scene of the alleged crime, the Villa Buchfinkenschlag. When Lina discovers the devastated house in a wild park, she encounters the former gardener Johann, an attractive but enigmatic man with a penchant for beautiful, poisonous plants. It is he who must come to Lina's aid when she naively puts herself in danger. In her garden mystery, Elsemarie Maletzke plays with the elements of the classic "whodunit," featuring bumbling witnesses, false suspects, hasty conclusions, and of course, the question of whether the gardener is the culprit.