Ol' Mama Squirrel has raised many babies and kept them all safe from predators, but she may have met her match when a determined grizzly bear threatens to eat her entire family tree.

"No grizzly has ever killed a human in Glacier National Park before... until tonight. Eleven-year-old Melody Vega and her family come to Glacier every year. Mel loves it here -- the beautiful landscapes and wildlife make it easy to forget her real-world troubles. But this year is different. With Mom gone, every moment in the park is a reminder of the past. Then Mel comes face-to-face with a mighty grizzly. She knows basic bear safety: Don't turn your...