Black Jack is filled with a variety of eccentric characters, including a twelveyear-old blackmailer, several traveling hucksters, and a "professional widow" who claims corpses of hanged criminals to sell to surgeons as cadavers. Tolly, the novel's central character, is a poor boy whose generous nature allows Black Jack to involve him in a series of frightening adventures.

BlackJack has spent his life waylaying travelers and killing them for their money, but he is not a totally unsympathetic character. Although he resents Tolly's attempts to reform him and sneeringly refers to the boy as his "little saint," Black Jack comes to have a grudging respect for the boy's principles. Initially, Tolly is terrified of Black Jack, but he also feels responsible for the convict.

When the two become separated, Tolly alternates between feeling relieved and wondering what the giant is up to.

Belle Carter is...