jeff probst gave me an exclusive look at a group of castaways like we've never seen before. reality show "survivor" is shaking things up, set in nicaragua, the cut-throat competition has a battle of the ages for the ages. what about the format this season? old versus young? tell us about that. >> we started looking and thinking, we have enough strong, fit, older people that we could try to do old versus young. >> reporter: series host and executive producer jeff probst leads 20 new contestants vying for $1 million prize and the title of sole survivor. to win it all they have to navigate new challenges designed to level the playing field between the tribes. >> you have young men and women running around, they're fit, they can do all these challenges but can they think? when you look at the older tribe, you see people that stop before they walk and they say, we should go this way. >> reporter: this tribe with castaways over 40 has one notable leader, two-time super bowl champion, jimmie johnson. >> he's applied two other times, got turned down both times because of medical. la