Orca researcher Dr. Deborah Giles and her scent-detecting dog, Eba, are racing to save the southern resident killer whales — an endangered group with just 73 members left. By tracking orca poop, they gather vital data on stress, pregnancy, diet, and health. With Chinook salmon populations collapsing, these orcas are starving, and Giles is fighting to change their fate — one scat sample at a time.