KCTS's Wildlife Detectives presents an hour documentary on recent sharks inhabiting Elliot Bay and Puget Sound. One of the world's largest and most elusive predatory sharks, the sixgill, suddenly appears in Seattle's waters. These creatures typically dwell in darkness several thousands of feet beneath the surface. Little is known about them. What would make them appear in the shallows of Puget Sound? And what does it say about our oceans? Researchers are hunting for answers.