Jed and Dr. Hyatt go undercover as members of a hobo community to protect a man known as Doc, acknowledged leader of the community. Years ago Doc was disinherited by his wealthy father for behaving irresponsibly with money, but now his dying father wants him back, and others in his family want him dead so they won't have to pay him an allowance. When Doc winds up inheriting the entire estate, he goes to town with it, making Checkmate's job more difficult.