Known only by her research number, Grizzly 399 has been a fixture in Grand Teton National Park since 2007, becoming the world's most famous grizzly bear. Now 399 is raising four cubs in the face of human encroachment, a warming climate, and the threat of losing protection under the Endangered Species Act as citizens from Wyoming, Idaho, and Montana attempt to remove grizzlies from the protected list. In a riveting story full of twists and turns, hope and heartbreak, Grizzly 399 stands as a symbol of the clash between humans and the wild.

• PBS