THE CASE OF THE ANNIVERSARY LIBATION is a murder mystery with its "detective" being the "clever Hebrew" Judah P. Benjamin of Louisiana. His amanuensis, Horatio T. Burdette, tells of a Huck Finn odyssey from boyhood, to student, to early fatherhood, all while he is a slave. The 88,500-word novel traces Horatio's boyhood at the Burdette plantations near the Gulf of Mexico. A drunken Rainey Burdette has already caused the death of a horse in an accident that broke the collarbone of the twelve-year-old Horatio. Days later, Rainey is drunk at Miss Ginny's Emporium when he uses Horatio as collateral during a poker game. Horatio ends up being the "property" of Captain Eagleton, an anti-slavery gambler who had served in the war with Mexico. At Omega plantation owned by the Osgoods, the Captain plays cards with the plantation owner and his guest, Senator Benjamin. As the Captain realizes he is dying from being poisoned, he deliberately loses Horatio to the Senator in a game of blackjack. He gets Benjamin to be his executor and writes a quick will in which he gives most of his money to his little boy in Charleston but sets aside enough for Horatio to be sent north for an education. After the Captain's death, three others die on the plantation. Benjamin continues his trip to Washington City, but leaves Horatio in the hands of people he can trust. Later, at Benjamin's plantation, he meets an old slave with a rhetorical gift and a girl named Sophie, who is a little older than he is. When in New Orleans and later in Chicago and Philadelphia, the Senator and Horatio pick up enough clues to solve the mystery of the poisonings at Omega Plantation.