Oenophile Oz Clarke takes novice James May around California's vineries in an RV. They meet Mike Benziger, owner of an organic estate. He maintains an insectry, where he breeds insects to eat the lesser bugs that damage his vines, and a sceptical James is silenced when he tastes the wine. Next, they visit the Gallo estate, a producer of affordable wines that flood the international market. Their hostess, Gina Gallo, is charming, but Oz and James sour her hospitality by having another argument.