Richard Todd, writer, can't write anymore. Despite having a comfortable home in the 'better end' of Dublin, a successful wife, Valery Hobson, who does everything for him and three well-adjusted children, he is paralysed by a sense of futility. His publisher sends Jenny Lambe, a talented young editor, to help him work on his latest book, about the assassination of Garfield. They fall for each other and Richard leaves his wife and family to move in with her to a small rental house on the outskirts of the city.
While researching the book Richard hears the voice of the Guiteau, who tells him he was not alone in the assassination - there was a mastermind behind the plot and Richard better find out who this was, or Guiteau will murder him.
Richard is visited in turn by the major players surrounding Garfield's death, including the President himself, his Secretary of State James Blaine, leading Republican senator Roscoe Conkling, Conkling's mistress Kate Chase Sprague, the investigating police officer, McElfresh and bungling Vice President Chester Arthur.
Aside from giving their views and evidence on the murder, they engage in discussion with Richard re his own behaviour and its consequences. Confronted with his own culpability and with growing feelings of guilt and grief, to go with incredulity, he must maintain enough impartiality to find the truth. Adding to his problems are an injured wife and an increasingly disillusioned mistress. Both women, with genuine reasons for anger and disappointment, pull him apart in their different ways. On top of everything else are financial difficulties, and growing pressure from his publisher. He must solve the mystery and write the book before either Guiteau catches up with him or he loses his sanity.
Both Blaine and Conkling present plausible cases as to why the other is responsible for the president’s death. For Blaine, it was Conkling and his followers, the 'Stalwart's' ruthless politicking and relentless deriding of Garfield that created the atmosphere, which made it possible for a madman like Guiteau to strike. From Conkling's point of view, Blaine in some way orchestrated the assassination in order to inherit the presidency, under the obscure pro-tempore rule, which places the Secretary of State in the Oval Office, if both president and vice-president are unavailable. Arthur, Conkling argues, would have had to resign in the event of Garfield’s immediate death, because of his close association with the Stalwarts. It was only Arthur’s exemplary behaviour during the three months it took the President to die, that saved his reputation and made it possible for him to accede to the role.
The novel ends with a court-room scene in the living-room of the rented house, where Guiteau presides from behind the news desk on Channel Four. Blaine and Conkling’s final arguments are interrupted by Detective McElfresh, who has been working with Chester Arthur. Arthur orchestrated a meeting with Guiteau in Lafayette Park and put him up to the murder with promises of political office. He ensured his silence by making him swear on the Bible - a promise a religious maniac like Guiteau could never break. McElfresh, who was used to keep him silent in prison, is rewarded with the post of Chief of Police.
Richard, already distraught by news of Jenny's pregnancy, collapses into a catatonic state. He is discovered by Jenny the following morning, who calls Valerie out of desperation. Richard is taken back to his opulent home where he has a final conversation with Garfield, before dying.
Finally, we find out it was Jenny who wrote this book, from the notes and files she found in Richard's study after he had gone. She has given Richard and his set the names of nineteen-fifties British film actors, to go with their wooden, middle-class personalities and values. Richard, who could not bend has broken, while Valery and Jenny who have learned compassion and to grow up respectively, strike up an uneasy friendship, for the sake of the baby.
