The novel is about two Scottish men, an atheist and an orthodox Roman Catholic. The two try to fight a duel to the death over faith and individual irreconcilable differences. But the duels are against the law, so they have to find a secret place to fight despite continuous intervention by the police. Duels are considered uncouth in Edwardian England, so is any public discussion of religion. Religion is a private matter. But they make a run for it across the English countryside trying to avoid the law and any philosophers who would try to stop them. The process of finding a place to fight and kill themselves peacefully devoid of authorities leads to several comic adventures.
The two men are filled with rage as they try to defend their views on religion. The rage makes both men take up swords every other time to defend their negative opinions on religion. The rage leads the atheist to print blasphemy and logical syllogisms. The story is a human document that progresses from unconventional to transcendental and embodies the struggle between material and spiritual. The storyline has less response to atheism as opposed to the immense complacency that it expresses. The war between the ball and the cross is symbolic of the dynamic and unbiased war between the two.
This novel's plot is more sympathetic to Maclan, the Roman Catholic, even though it sometimes indicates that Maclan was in some ways too extreme. Turnbull, the atheist, as well, is presented in some sympathetic light but not as much. Their desire to duel fight leads to the development of a particular partnership that evolves into a friendship. The outside world is the real antagonist who desperately tries to prevent a duel between the two over a 'mere religion.'
