In El Paso in 1877, a young man saunters into a bar and scans the room. He approaches Joe Grant, who admits he's looking for someone. The young man asks to examine Grant's gun and unloads two of the bullets. Grant says he's searching for Billy the Kid, then determines that's who he's looking at. Grant is dead before he reaches a loaded chamber of his gun. Billy flashes back to six years earlier in New York City, when he was 12-year-old Billy McCarty. His parents, Patrick and Kathleen, decide to move west seeking opportunity, although his father has doubts. They have trouble finding affordable transportation. Billy meets Moss, an old, one-eyed man who will take them there for cheap. A wagon capsizes crossing a river and most possessions were lost. Patrick almost drowns trying to save the family's chest. Family friend Frank O'Connor is killed in a skirmish with horse thieves. Moss trains Billy how to shoot. They arrive at Coffeyville, which is barely a clearing in the road. Billy sees a tree get set on fire by a lightning strike during a thunderstorm. Kathleen arranges for her and the boys to do housekeeping in return for a room at a boardinghouse. Patrick has been weak since his near-death experience. The local doctor diagnoses him as mentally ill. Mary O'Connor goes back to New York. A banker cruelly turns down Kathleen's request for a loan. Billy takes his pen. A priest comes to give Patrick last rites. Billy says goodbye to Patrick. After Patrick's funeral, Billy picks up a gun. In the present, Billy informs the bar's patrons that he didn't want to kill Grant, who insisted on trying to collect the bounty on Billy. He even left money with the bartender to pay for Grant's funeral.