Professor Tarantoga saves human civilization! After using his chronopad to investigate the leading scientists and artists in history, Tarantoga concludes that without exception they are lazy drunkards. So naturally, he sends smart young people into various eras to invent differential calculus, to paint the Mona Lisa, etc.—all while a pair of police inspectors have their eye on him.

The three principal Trekkers find themselves on a planet where everyone is being evacuated to the past to escape an impending supernova.