Something is killing organisms from dolphins to dogs to humans on Vancouver Island, British Columbia. What is it? How did it get to the island? How is it transmitted between organisms? This interrupted case study is designed to teach students at the introductory biology undergraduate or AP high school biology level about the importance of organismal diversity in uncovering the culprit behind the outbreak of a real-life illness. The case is presented in an interrupted format in which students work progressively through the sections, gradually gathering more information, responding to questions that do not always have definite answers, thereby giving students a taste of how real science works. The intent is for students to use their knowledge of major organismal groups learned in class to figure out this true-life “who-done-it.” The case can be used as a review of major organismal groupings at the classification level of domain and kingdom.  Basic organismal characteristics of prokaryotes and eukaryotes are highlighted, and mechanisms for origin and transmission of organismal outbreaks are discussed.