New host Dan Harris (ABC's "Nightline," "Good Morning America: Weekend Edition") welcomes a fresh group of bona fide genius contestants to the ultimate test of intellectual skill and endurance.

Season two kicks off with all-time greatest "Jeopardy!" winner and best-selling author Ken Jennings entering the intellectual arena of "500 Questions." Having won an impressive 74 times on "Jeopardy!" and breaking American game show records along the way, how will Ken fare when he tackles the toughest game ever devised?

New for season two is the addition of a bonus two-minute lightning round, which will challenge the contestant to answer as many questions as possible, without getting three wrong in a row, in an effort to earn more money to their bank and increase their overall score.

"500 Questions" challenges the smartest people in the country to achieve the seemingly impossible task of answering 500 of the most difficult general knowledge questions ever devised. There's only one simple rule: never get three wrong in a row — or you're done. No saves, no helps, no multiple choice, "500 Questions" keeps you on the edge of your seat to see if any of these geniuses can do it. It is the ultimate test, where intellect, strategy and stamina are all equally essential in order to win.