Hosts Jeremy Clarkson, Richard Hammond and James May (with their mysterious assistant, The Stig, of course) undertake an American road trip, where they take iconic supercars for a spin through Las Vegas and Los Angeles, race against fighter planes and end with a hair-raising run to the Mexican border. The hosts embark on another epic trip to find the source of the Nile River in three station wagons with a not-so-stellar knowledge of African geography.