Actor Joseph Gordon-Levitt tackles Kenya's unyielding terrain with Bear Grylls. Dropped into the elements from a helicopter, Joseph and Bear navigate a perilous rappel, milk a camel for needed hydration, and ascend a massive rock dome that tests Joseph's fear of heights like nothing before. As the duo battles a crocodile for the remains of a water buffalo that is their only hope for dinner, Joseph details his rise to fame and his efforts to honor the memory of his beloved brother.

Bear takes Lena on the ride of her life as they paramotor deep into the remote Spanish wilderness. Continuing on foot, they traverse a towering, razor-thin ridge before a dead-end forces a harrowing rappel. After securing a dinner of bone marrow from a goat carcass, the two must cross a lake using a makeshift raft as an unexpected storm wreaks havoc. As they battle the elements, Lena grants us exclusive details of life on "Game of Thrones," her rise to stardom, and her battle to overcome depression.