a veteran of two combat tours. now he is about to return to afghanistan to an area the military calls hell on earth. >> and then there's 18-year-old will mclean who weeks from tonight may find himself carrying out the president's mission, into the very heart of afghanistan. >> jason carroll joins me now. we've watched as you've put these stories together over time. i guess we all go into stories about the military with our own preconceived notions. what surprised you most as you followed these three? >> you know, there were several surprises along the way. again, just to reset the clock here, the reason why initially i got involved in the series and wanted to do it, i don't come from a military family, ali, and i wanted to give people like myself and other folks out there a real chance to see what