Transcript for Real-Life 'Designated Survivor' Stories Behind New ABC Show
It may have been spun into a Hollywood tale but the idea of a designated survivor is in fact very real. Each year there's one secret person who's ready to assume the top job in the event our government is wiped out. What's it like to be a real-life designated survivor? Here's my "Nightline" coanchor juju Chang. There's some kind of explosion in or around the capitol building -- Reporter: It is the unthinkable. The doomsday scenario. A catastrophic attack on U.S. Soil. The president, congress, the upper levels of government, all wiped out. While it's the stuff of dark thrillers, the creators of ABC's most talked about show "Designated survivor" have something very real in mind. Sir, you are now the president of the United States. So this is your presidential motorcade? I'm seeing it for the first time. This is a small one. Normally there's about 16 cars. Reporter: The series marks a return to television for Kiefer Sutherland, playing a meek, low-level cabinet secretary. I, Thomas Adam Kirkman, do solemnly swear -- Reporter: Who's thrust fully unprepared into the role of president. It's based on a very real, extremely classified safeguard, known as the continuity of government plan. The problem that the continuity of government plan tries to solve is something called decapitation. Reporter: ABC news consultant and former counterterrorism official dick Clark ran the program. He's the only official to ever deploy it in a crisis. During 9/11. While president bush was in the air, vice president Cheney was rushed to an underground bunker. On 9/11, I activated the system. The continuity of government system. And we asked the speaker of the house to leave Washington. We landed a helicopter on the grounds of the capitol, got the speaker to the helicopter, and flew him out of Washington. Because we didn't know at that point whether or not the white house or the capitol were going to be hit by hijacked airplanes. Reporter: It's like something out of a spy novel. Using secret nuclear-proof bunkers like this now-declassified one under the posh greenbriar hotel in the mountains of West Virginia. The concept, a remnant of the cold war. But each year a cabinet member is still asked to skip the state of the union address. They are put in a secure location with a support staff before the state of the union begins, and they're brought back only the neck monxt morning. Reporter: Former U.S. Attorney general Alberto Gonzalez once served as designated survivor during president bush's 2007 address to joint houses of congress. Madam speaker, vice president Cheney, members of congress, distinguished guests -- My FBI detail drove me to Andrews air force base. There were a group of individuals there from various departments and agencies all carrying these black binders. Their job was to advise me in the event that I assumed the presidency. Then I settled in in front of a large monitor and watched president bush give his state of the union. We must have the will to face difficult challenges -- Reporter: He talks about his experience in his new book "True faith and allegiance." It suddenly hit me in the middle of that speech, oh my gosh. I looked around the airplane. I thought, oh my gosh. I've experienced pretty big moments before with president bush. I've advised him through two wars. I was on the oval office porch on the evening of September 11th when president bush came home that historic day. It really kind of hit me sitting on that airplane. I looked around the plane. At those that were with me. I wondered, would we be up to governing a wounded nation? Where's the president? In the bunker. Reporter: The white house going down is often a Hollywood plot line. Whether it's rogue foreign terror cells in "Olympus is fallen" -- Olympus is fallen! They're taking the white house! Reporter: Two-timing double agents on air force one -- Get off my plane! Reporter: Or tentacle-covered alien invaders on "Independence day." Welcome to Earth! Reporter: This time a marquee terror attack. The show invited us to this warehouse turned Navy S.E.A.L. Training base. This will be the area where you actually film the scene? He and I will be here. They'll be actually training through the compound. Action! Reporter: The action scenes are high-octane. But pondering how an average Joe might react to suddenly becoming commander in chief -- Where are we going? Presidential emergency operations center. Reporter: Is what makes "Designated survivor" a thinking man's thriller. This character has to spend a lot of the time thinking about what it means to be a good president. What it means to be a good leader. What do you think it takes to be a good president? I think maybe you have to try and not be a good president. You have to try and be a good person. You're also one of the eps on the series. Do you ever get tempted to bring the current presidential climate into this storyline? I think it's impossible not to. Certainly in the context of our show, we have an opportunity to overcome the divide that seems to have taken hold in America. Give me a kiss. Mwah. Good night, daddy. It's nice to see him play a loving, sweet family man. Is that a side of you the audiences are going to be able to connect to? I think over the course of "24," we made 216 episodes, I think the only time he smiled when is he shot Nina Meyers. So I smile a lot more in this show. Reporter: Sutherland is referring to counterterrorism agent jack Bauer. His bad-ass alter ego for neek nearly a decade on "24." Your character is not a hard-core political operative. He's also not jack Bauer. Not by a long shot. I'm looking behind me. All of these weapons. My character wouldn't know how to hold that, let alone fire it. Jack Bauer was very practice efficient in that. The one thing they do have in common this is commitment to serve publicly. This is the nuclear football. In the pilot they bring out the nuclear football. You say, what's the code? Do I have an eye scan? Do you need my fingerprints or eye scan or something? No, sir. It's not like the movies. The guy laughs and says, yeah, we don't do that. Reporter: The show going to great lengths to keep things realistic. We're here on the Toronto set of "Designated survivor." The cast and crew hard at work. All of this is the stand-in for a swanky neighborhood in Alexandra, Virginia. Every detail well thought out. All the way down to the Washington news van. The president's speechwriter, veteran actor with real-life white house cred. Mr. President, maybe the country's not ready yet. Reporter: Kal Penn, everyone's favorite stoner from "Harold and Kumar." Even played a terrorist on "24." Then famously left Hollywood to serve in the office of public engagement in the Obama administration. Compare and contrast the working conditions inside the beltway versus inside Hollywood. You can't, though. Come on. It's so far-fetched. Look, I have an air conditioned trailer and somebody will bring me a coffee if I want it, here. There -- You're in cramped quarters. I'm eating vending machine sandwiches and working 19 hours a day. I love that. But this is definitely the make-believe version. Reporter: On set Penn became a fact checker. The kal Penn seal of approval? Flattering. It's little things. How many people would be in a particular office? Would somebody actually run into this person or are we taking creative license with it? Reporter: They brought in a hard-hitting political consultant from Washington, D.C. You are a speechwriter. I was for two senators and four cabinet secretaries. Worked on a couple of state of the union addresses. Sorry, sir, I told him you were busy. That's all right. How can I HP you? How realistic is the oval office you built? Remarkable. In the white house men's room there's an old-style mechanical shoe buffer with red and black brush, we have that. We've gotten down to fine detail. That's weird. Reporter: While they might not get everything right -- no doubt all the drama will feel true to life. Our thanks to juju for that report. You can catch "Designate D survivor" here on ABC Wednesday at 10:00 P.M.
This transcript has been automatically generated and may not be 100% accurate.