A coming-of-age story set in a vast, cross-country landscape, "Arcadia" begins when twelve-year-old Greta's dad wakes her up before dawn and crams his three kids into a dented station wagon. The family sets off on a 3,000-mile journey from the New England woods to the California desert, as Dad paints pictures of a California paradise and assures the kids that Mom will soon join them.

Greta believes him at first, mesmerized by the strange new scenery and clinging to her stuffed bunny Harrison. Older sister Caroline nonchalantly accepts his stories, more focused on the boyfriend she's leaving behind. And nine-year-old Nat, too young to suspect a thing, is eager to see the epic Grand Canyon. But Dad's mood shifts as often as the landscape outside their window, and the kids soon find themselves in increasingly unpleasant and even dangerous situations.