Stan arrives late to a CIA nuclear drill and thinks it's real. He decides to move the family into the mountains to survive the apocalypse. Even though he realizes his error, he begins to enjoy the attention that he gets from the family so much that he doesn't tell them the truth. However, when the family meets a mountain man and learns the truth, Stan has some explaining to do.
The show revolves around C.I.A. Agent Stan Smith, and his not so average family. Stan is constantly fighting off terrorists who threaten the safety of the United States, sometimes causing more harm than good.
His wife Francine is your average house wife. She juggles Stan and the kids while keeping a sound mind. Hayley, Stan's only daughter, is your average rebellious teenager. She speaks her own mind, and does things her own way.
Steve, Stan's only son, is a bit of a "geek". He enjoys games like Dungeons and Dragons, and participating in comic book conventions. Although he's not Stan's dream son, he always makes him proud.
Then there's Roger, the illegal alien (literally) who the Smith's are keeping protected. Roger deals with your average alien emotions, and the fact that he is not allowed out in public, which causes him great distress.
Last but not least, Klaus, the Smith's wisecracking talking fish (well, after he was removed from his body) who is secretly in love with Francine.