Jack Osbourne, first son of the world's most famous TV family, is on a mission. He wants to take on one of the planet's most extreme climbing challenges - El Capitan in Yosemite National Park, El Cap is a vertical kilometre of sheer rock in California's Yosemite Valley - an extreme undertaking even by the standards of hardened professionals. There is a small snag in this plan - Jack is virtually a complete novice at climbing, unfit and About 50 lbs (26 Kilos) overweight.