 The three-part story begins with Doc Adams returning to Dodge City after an absence, which lifts the spirits of the town. Later, Matt is shot by a criminal. The bullet is lodged near his spine. Doc says he s incapable of the intricate surgery necessary to remove the bullet. As a result, Doc transports Matt by train to Denver, where a specialist awaits. Kitty, Festus and Newly also decide to make the trip. The U.S. Army is also using the train to transport gold, which is the target of a gang led by Jack Sinclair -- who lost a hand because of Dillon. Matt, laying face down and virtually unable to move, would be a sitting duck if Sinclair discovers he s on the train.