They set out conspicuously, in a single line in a play, or at the head or tail of a paragraph, remarks of this challenging kind; as when Mr. Bernard Shaw wrote: "The Golden Rule is that there is no Golden Rule"; or Oscar Wilde observed: "I can resist everything except temptation"; or a duller scribe (not to be named with these and now doing penance for his earlier vices in the nobler toil of celebrating the virtues of Mr. Pond) said in defence of hobbies and amateurs and general duffers like himself: "If a thing is worth doing, it is worth doing badly."

The main characters in the book are Mr. Pond, his friend Captain Peter Gahagan, a romantic and impulsive Irishman, and a well-known government official, Sir Hubert Wotton.

Also mentioned in more than one chapter are Violet Varney, an actress, and her sister Joan, to whom Gahagan proposes after being suspected of having an affair with Lord Crome's wife in "Ring of Lovers".

The paradox is introduced when a casual discussion turns to matters of European politics, and Pond recalls an episode during a war between the Prussians and the Polish.

Marshal Von Grock failed in his attempt to execute the influential Polish poet and singer Paul Petrowski because two of his soldiers did precisely what he asked.

Wotton tells the story of how Pond saved England and was shot at five times in a railway station waiting room, all because of the "pencil" which made the "black marks".

In the capital of a European republic with an oppressive government and an active revolutionary movement, Mr Louis sits in the central square and entertains all and sundry.

The captain tells a (true) story of a dreadful dinner party which ended in death, and explains how it induced him to propose to the woman he loves.

Green introduces the Vicar of Hanging Burgess, who accuses Captain Gahagan of having, many years ago, shot a rival in love, dumped the body and then run away to the war.