Peter Leverett, the first-person narrator of Set This House on Fire, is a lawyer in New York plagued by disturbing memories of and questions about events in Sambuco, Italy, several years earlier, which he partially observed and which culminated in the rape and murder of a young, beautiful Italian, Francesca Ricci, and in the death of Mason Flagg. Mason, a millionaire American temporarily in Sambuco, is found at the base of a cliff a few hours after the brutal attack on Francesca, and the Italian police decided an enraged, lustful Mason attacked Francesca and then killed himself in remorse. Having known Mason since their high school days some ten years earlier and believing him to be sexually obsessed but not a murderer, Peter has difficulty accepting the official explanation. After seeing a New York Times political cartoon drawn by Cass Kinsolving, another American who was in Sambuco when Mason and Francesca died, Peter decides to contact Cass and get his version of what happened, particularly since Cass seems somehow to be involved.

Peter leaves New York for Virginia, where he grew up and where his parents still live, on his way to visit Cass in Charleston, South Carolina. In Virginia, Peter finds his hometown drastically changed and virtually unrecognizable, modernized and urbanized, and street names changed, such as “Bankhead Magruder Avenue” becoming “Buena Vista Terrace,” prompting Peter’s father to comment that “it’s the California influence . . . it’s going to get us all in the end.”

In Charleston, Peter narrates, via personal flashback and quotation from Cass’s comments and notebook, their experiences and observations prior to and after their arrival in Sambuco which, in totality, reconstruct the earlier reality and generate the truth about Francesca’s rape and murder and Mason’s death. First, Peter relates his school-based knowledge of Mason, a Northerner transplanted to Virginia because his unaffectionate movie-mogul father bought a plantation there, a place of entertainment for his movie-star friends. Peter also explains Mason’s unusually close attachment to his alcoholic, virtually deserted mother and relates Mason’s dismissal from school after his drunken seduction of a thirteen-year-old, imbecilic girl.

Peter then tells of his arrival in Sambuco on the afternoon before the murder, interrupting filming of a movie scene; a movie company was in Sambuco partially because of a tie to Mason. Next, Peter describes the movie crowd’s raucous party and the mysterious scratches around Mason’s face. He also observed Mason pursue and threaten to kill a young Italian girl who, with her dress torn, ran from his residence. Later, Peter observed Cass kiss this same girl (Francesca) and observed Mason receive a note that said, “You’re in deep trouble. . . . I’m going to turn you into bait for buzzards. C.” Peter then watched Mason humiliate a drunken Cass by coercing him to perform a “trained seal” act for the movie crowd (recite bawdy limericks, pantomime the behavior of a French whore, and sing “Old Black Joe,” and do the “rebel yell,” among other activities). Rescuing Cass from this humiliation, Peter went with him to deliver medicine (stolen from Mason) to Francesca’s dying father. Peter then slept, awakening to the news of Francesca’s rape and murder, and Mason’s death.

Peter next presents Cass’s account of his life prior to coming to Sambuco—his lower-class southern childhood, his determination to become a successful artist, his horrifying World War II experiences, and his subsequent mental problems, including an inability to successfully paint but desperate need to do so and an inability to avoid the alcohol consumption that seemed to dull the pain of his artistic failure but that actually...