Over the past four years, Jack Osbourne has climbed the vertical kilometre of El Capitan, fought physical bouts in Thailand and India, jumped off the world's highest bungee platform and taken on the most gruelling endurance race in the world. Now, he faces his toughest, most extreme, most arduous set of endurance challenges and adrenaline hits yet - and he'll be taking a cast of his well-known friends along too. (6 x 1hr)