When an asteroid hit the earth thousands of years ago, it left behind a deep crater and lots of extraterrestrial debris. There, in 1950s America, schoolchildren and their parents travel across the country to the remote desert town of Asteroid City, where the Junior Stargazer Congress is taking place. In addition to the families, astronomers, teachers and the military also respond to the call of this major event. But instead of the planned scientific competition, unexpected world-changing events occur, causing chaos and confusion - as is the case when an alien suddenly appears. The military doesn't hesitate and declares Asteroid City a no-go zone without further ado.