The central characters of The Burden of Proof are nearly all members of the Stern family. At the center of the novel is Alejandro "Sandy" Stern, Rusty Sabich's enigmatic defense lawyer from Presumed Innocent. As this novel indicates, Sabich's trial had increased Stern's practice and he seems the model of the successful professional man. However, when he comes home to discover his wife dead in the garage with only the note, "Can you forgive me?", the fifty-six-year old Stern is forced to face the deficiencies and failures in his life.

He comes to realize that he had chosen to avoid looking at the darker aspects of his wife, including the fact that she had always been an unhappy woman, full of secrets. As flashbacks in the book reveal, he had found Clara's past a mystery; he had never really understood how he, a poor immigrant, had been able...