The narrative starts years later, when Kegan's half-brother, Nick, witnesses the death-bed confession of a man claiming to have been part of the killing's 'hit squad'.

The character "Joe Diamond" is the fictional representation of the killer of Kennedy's assassin, Lee Harvey Oswald, the Mob-connected Dallas nightclub owner Jack Ruby.

Condon's book describes numerous intertwined threads, variously implicating (or proffering as diversions to put the protagonist off the trail) the Jewish/Italian-American Mob, figures related to Cuba, even possible domestic police connections.

Only in the final act, in which Nick meets with his vicious and perverse Joseph P. Kennedy-like 'father-figure', is the truth revealed with a twist ending implicating the "system" of interrelated interests embracing organized crime, the U.S. covert world, big business, and political fixers.

In 1979, a film adaptation of the novel was released, Winter Kills, which starred Jeff Bridges and John Huston.