Jerry Harlowe, his wife, and his fellow neighbors through a birthday surprise party for Dr. William Stockton. They jokingly note that Stockton's bomb shelter project has led to some late-night hammering noises and concrete trucks coming through at odd hours. Harlowe calls for a toast and thanks him on behalf of his neighbors. They're interrupted when Stockton's son Paul tells them that the TV has gone off the air and told everyone to tune to the radio. Stockton tunes in the channel and the announcer goes on the air saying that unidentified flying objects have been detected and a state of yellow alert has been called. The announcer advises anyone to go to a shelter if they can and all of the couples leave for their homes.
Stockton and his wife Grace prepare for the worse and take as much food and water down to their shelter as possible. The water cuts out and they go down to the shelter where Grace notes that there's not any point in surviving if they're the only ones left amidst a radioactive landscape. Paul calls his father up and Stockton tells Grace that they have to survive for their son. The radio makes another announcement and as Stockton gets their water, Harlowe comes by. He note their house is new and has no basement and wants to use Stockton's shelter. They start to fight and Harlowe tries to get hold of himself but Stockton says he tried to warn them and now it's too late. Marty Weiss and his family come and beg for shelter as the lights go out. Stockton has no choice but to turn them away. A furious Marty pounds on the door, accusing Stockton of being a killer.
Harlowe's family comes over with the Hendersons and Harlowe tries to calm them down, noting that the shelter won't hold all of them. Marty suggests they convince Stockton to let one family in and the Hendersons turn on him, accusing him of being a pushy foreigner. As the planes soar overhead, Frank and other neighbors go back to the basement and demand that Stockton let them in or they'll bust the door down. He refuses and they start thinking about getting a battering ram to break it down. When they talk about the next street over as potential enemies, Harlowe points out they're turning into a brainless mob. Weiss tries to calm them down but Frank punches him. The sirens go off and Henderson and the others go for the battering ram. They knock down the door just as the radio comes back on to announce that the unidentified objects have been identified as satellites.
Henderson apologize to Weiss and Harlowe suggests they gather up a collection to repair the damages. Weiss suggests they have a block party and get back to normal but Stockton wonders if what they've seen is when they're really "normal," and if they were destroyed even without the bomb.