Llewelyn Moss (Josh Brolin), out hunting antelope near the Rio Grande, comes across a drug deal gone sour - sour enough to leave behind a cache of heroin, two million dollars, many corpses and one dying Mexican who begs for water. Making off with the money, Moss becomes undone by his conscience. Going back to take water to the dying man, he's discovered and identified by gunmen. Narrowly escaping the drug runners, he sends his wife Carla Jean (Kelly MacDonald) to safety. A taciturn man, Moss neither reveals to his wife, nor to audience, what his plans are.