The elephant Echo, who was the focus of books, documentaries and two previous "Nature" episodes, died in May 2009 at the age of 65. This installment celebrates her life and examines how her death has impacted her family, which faces the worst recorded drought to hit their home (Kenya's Amboseli National Park) even as they deal with their grief. Included: archival footage of Echo; remarks from filmmaker Martyn Colbeck and elephant expert Cynthia Moss, who both observed her for decades.