Twenty miles into a marathon in a remote part of New Mexico, Karen Williams finds herself caught between a bear and her cub; Steve Campbell is working on an oil pipeline in Alberta, Canada, when a mountain lion attacks him.

A triathlete is attacked by a bull shark while training in Alabama. After being bit by a rattlesnake, a father fights to survive. A couple is attacked by a giraffe on vacation in Zambia. And a girls' trip turns deadly in Cancun.