Valiant Gentlemen, by Sabina Murray, is historical fiction. It tells the story of real-life historical figures Roger Casement, an Irishman and political activist, and Herbert Ward, an Englishman and artist. The men have a friendship that spans 30 years, but it is ultimately torn apart when Casement is tried for treason.

The novel begins when Casement and Ward are in the Congo arranging porters for an expedition. Henry Morton Stanley arrives and Ward decides to join his Emin Pasha Relief Expedition against the recommendation of Casement who believes Stanley is a charlatan.

Casement begins working for missionaries when he decides that he does not want to be a part of the mistreatment of the natives.

Ward gets involved in a scandal when Stanley’s expedition goes horribly wrong. Because of the contract he signed, Ward is unable to defend himself, so his reputation is ruined. Casement suggests that he write a book about his life in the Congo and go on a lecture circuit to promote the book.

While on a ship bound for America to begin his lecture circuit, Ward meets Sarita Sanford, a wealthy heiress. Casement comes to see Ward speak in America and has his first homosexual experience. He feels guilty and dirty afterward.

Sarita and Ward get married. Sarita gets pregnant soon afterward.

Casement returns to the Congo and meets Joseph Conrad, to who he gives advice before Conrad sets out to explore. Casement’s hired native boy, Mbatchi, is nearly kidnapped. Casement believes the men were going to enslave Mbatchi.

Sarita’s family loses their fortune and Ward worries about how he will support his wife and child. He continues on the lecture circuit. Sarita has a baby girl, whom they name Sarita Enriqueta, but call Cricket.

Casement visits his cousin Gee and sister Nina. Nina takes them to see Stanley lecture. Casement visits Ward and meets baby Cricket. Later, he catches a boy who snatches a purse from an older woman, then he goes to a Turkish bathhouse.

Ward begins painting at a studio. Sarita models her feet for one of the artists and feels less confined in her marriage.

Casement returns to Africa. There is a flood while he is travelling with a caravan and he saves a man from drowning. Then he attends a party with the MacDonalds where he and other Europeans talk about the Hut Tax and the moral code of the natives.

Ward and Sarita, who now have three children, go on a boating vacation. Ward receives a telegram from Harmsworth asking him to travel with a polar expedition to write an article for his newspaper about it.

Sarita’s father regains his fortune.

Casement has surgery and recovers at Ward’s house. The two of them get drunk and Casement helps Ward get ready for bed. Ward falls backward into Casement and they fall to the floor where Ward passes out in Casement’s arms. Casement wakes in his own bed in the morning. The next night while staying at Ward’s house, he hears footsteps outside his room and thinks someone enters during the night. Sarita tells him it could not have been one of the children.

The Boer War starts in Africa. Casement sits in a tearoom with Miss Kingsley, a fellow explorer, and a soothsayer tells him he will die at the age of 52. Casement is sent to Brussels to talk to King Leopold about export taxes. He tries to convince Leopold to end slavery in Africa.

Ward starts sculpting. Casement visits and tells Ward he is writing a report about the brutal conditions in Africa. Ward worries that Casement may get himself into trouble with powerful people. Casement returns to Africa and begins gathering stories of the atrocities committed there.

Casement travels to Ireland to reconnect with his homeland and the Irish people. He is out of money and writes to Ward asking for money. After some time, Ward sends the money. Casement spends time with Biggers, who teaches Irish youth about Irish history, and Alice Green, who is an activist.

Ward and his sons go to watch an airplane experiment with Harmsworth. Charlie becomes interested in flying.

Casement visits the Wards again and Sarita is glad to have him there because Ward was depressed after their falling out over money. Sarita had finally convinced Ward to send Casement money. Ward is increasingly worried about Casement’s involvement in politics.

Casement leaves for the Amazon where he gathers information about the treatment of the natives there. He believes the conditions there are actually worse.

Casement grows more involved in Irish politics. There is an impending war with Germany and Casement thinks the Germans may be the answer to liberating Ireland from English rule. He helps raise funds to purchase guns from Germany.

War breaks out. Casement plans to arm Irish prisoners of war with German guns to form an Irish Brigade. The Wards flee from their home in France when the Germans invade. Charlie becomes a soldier. Ward eventually joins the ambulance corps, but returns home after injuring his knee and discovering that his heart is so weak that he cannot have knee surgery. Herbie becomes a pilot in the RAF.

Casement visits Irish prisoners held in German prison camps. A prisoner tells him that they will not fight against the English because they have fought beside them. He also tells Casement that if Casement returns, the Germans will kill them all. Casement is placed under investigation for his involvement with the Germans. Ward is questioned by the Foreign Office about his friendship with Casement.

Casement is captured and tried for treason. He is found guilty and is hanged. Sarita asks Ward why he did not visit Casement in prison or at least write to him. Ward answers that he could not and Sarita calls him a coward. Ward tries to convince her he is not a coward by travelling to the Far East. His heart is week and he dies.