America is addicted to oil, consuming 400 million gallons of gas every day. That’s more than a half million dollars spent on gas every minute of every day. Oil is the biggest business in the world and it is an industry that last year earned $180 billion in profits – one gallon at a time.

Over a Barrel: The Truth About Oil examines the United States’ profound dependence on oil. At the heart of the documentary is a salient question asked by ABC News anchor Charlie Gibson in interview after interview: what is the true cost of oil? The country's addiction, it turns out, has hidden costs. To help us understand those costs, Gibson examines the production pipeline, from the gas station where it ends, to the offshore rigs where crude oil is pumped from beneath the ocean floor.

Where does gasoline that we put in our cars come from? Why does the price go up or down? What role do refineries play? What has been the impact of the wars in Iraq? To answer basic yet elusive questions about the relationship between American’s and oil, Gibson travels across the country stopping at key links in the production chain.