The National Center for Case Study Teaching in Science, which is housed at the University of Buffalo, is a National Science Foundation-sponsored, award-winning program that brings together various peer-reviewed case studies in order to enliven science education at the secondary and university levels. This particular case concerns an "unusual mortality event" (UME) of dolphins on the East Coast of the United States in the year 2013. The case study follows a journalist and four scientists attempting to solve the mystery. It then puts students in the role of investigators, asking them to read, compare, and interpret various explanations of the events, in the process learning the scientific and social aspects that likely intersected to cause the dolphin deaths. The entire case may be downloaded for free as a PDF. Teaching Notes and Answer Keys are also available.