Barney Custer of Beatrice, Nebraska, U.S.A, decides to visit Lutha, the small European kingdom that was his mother's homeland. The current monarch, King Leopold, has been kept imprisoned for years by his scheming uncle, Prince Peter, who has put it about that he is insane, but breaks free from his imprisonment around the same time Barney arrives. Coincidentally, the two men bear a strong physical resemblance; confusion, hilarity, and adventure ensue.
(The Prisoner of Zenda? No, never heard of it. Why do you ask?)
This novel contains examples of:
- Altar the Speed: Barney's parents in the backstory.Neither his mother nor his father had ever returned to the little country since the day, thirty years before, that the big American had literally stolen his bride away, escaping across the border but a scant half-hour ahead of the pursuing troop of Luthanian cavalry.
- Bookcase Passage: Blentz castle has a network of secret passageways, with entrances behind fireplaces and portraits, used by both the heroes and the villains.
- A Child Shall Lead Them: The boy king Leopold before his imprisonment.
- Contrived Coincidence: All over the place, but perhaps the most egregious is the entrance to the secret passageway in the very room the villains keeping locking people in.
- Damsel in Distress: Emma von der Tann meets Barney Custer when her horse runs away with her on a perilous mountain road and he rescues her.
- Death by Irony: Near the end, the villains give up on assassinating Leopold and decide to try getting back in his good books by assassinating Barney, since Leopold has become paranoid that Barney will try to steal his life, throne and fiancée. Meanwhile, Leopold has realized that for Emma it really is Barney or nobody, and hits upon a scheme to trick her into marrying him by impersonating Barney — whereupon he gets killed by the villains.
- Death of the Hypotenuse: King Leopold gets killed off near the end so that the way is clear for Barney and Emma to marry.
- Emergency Impersonation: Barney is called on to impersonate King Leopold, for the good of Lutha, on several occasions.
- Exact Eavesdropping: A conspiracy against the king conveniently gets discussed on the other side of a thin partition from Barney.
- Exact Words: On the occasions when Barney is playing the role of the king, he exerts himself to avoid speaking any untruths, thus frequently making statements that are technically true but not in the way his listeners think. He gets a lot of use out of the convention of the royal third person, saying things about the king that people take to be referring to himself.
- Evil Uncle: Prince Peter.
- Faint in Shock: King Leopold faints when he realizes that he's going to be executed as a traitor if he can't convince anyone that he's himself and not his fugitive Identical Stranger cousin. One of many repeated reminders that Leopold is not an admirable manly man like the novel's hero.
- Fake Faint: Emma faints exactly once, and that's only a fake faint to buy time at her wedding, when she realizes Leopold has taken Barney's place.
- First-Name Basis: Emma recounts when a child, the prince had insisted on her calling him "Leopold" and made her kiss him every time she called him "highness".
- Hollywood Glass Cutter: Barney cuts a hole in a window using a diamond ring borrowed from Emma.
- Humiliating Wager: One of the details that contributes to Barney being mistaken for the fugitive king is a full beard which is explained as the result of him having lost a election bet with the forfeit that he would wear a green bonnet trimmed with red roses for six months, or forego shaving for an entire year. His attempts to explain why he has the beard to Luthanian officials who have never heard of these kinds of bets confirms in their minds that he is indeed mad, and thus must be the King.
- Hunting "Accident": Proposed for Ludwig von der Tann by the villains.
- Identical Stranger: Barney Custer of Beatrice, Nebraska, U.S.A, is taken for the king of Lutha. In the first half, it's explicitly stated that they are not truly identical in appearance, only sufficiently similar that the description of one matches the other, and the people who make the mistake have only the description to go on, as the king has been sequestered out of the public eye since he was a boy. In the second half, Burroughs slips into a more standard identical-stranger plot, with even those close to the king or to Barney not being able to spot the deception when Barney is dressed as the king.
- Improvised Weapon: Barney is attacked from behind, but sees his attacker reflected in the glass over a framed picture. Not having a proper weapon to hand, he takes the picture off the wall and hits his attacker with it.
- I Have You Now, My Pretty: Captain Maenck to Emma von der Tamm when she is a prisoner of Prince Peter's men.
- Nice to the Waiter: Ludwig von der Tann. One of the villains is aware of it, but considers it a bad point:You know the old fox has always made it a point to curry favor with the common soldiers. When he was minister of war he treated them better than he did his officers.
- Regent for Life: Prince Peter's goal in having the young king Leopold declared mad and locked away.
- Revealing Injury: Near the end, Barney and Leopold get injured in different places during a fight, which leads to a couple of people penetrating the last impersonation of the novel when they realize the man they're looking at has the wrong injury.
- Revealing Reflection: Barney is alerted to an attack from behind by the reflection in the glass of a framed picture.
- Royal Blood: Barney learns that his mother was a member of the Luthanian royal family, the aunt of the present king.
- Ruritania: Lutha.
- So Much for Stealth: A night-time burglary of Prince Peter's bedroom goes without a hitch until, on the way out, Barney catches his foot on an obstacle, making enough noise to rouse the prince.
- Tempting Fate:They were only about fifty feet from the highway. The girl touched his hand again. "We're safe," she cried, her voice vibrant with excitement, "we're safe at last." From beneath the bonnet, as though in answer to her statement, came a sickly, sucking sputter. The momentum of the car diminished. The throbbing of the engine ceased. They sat in silence as the machine coasted toward the highway and came to a dead stop, with its front wheels upon the road to safety.
- Ungrateful Bastard: King Leopold isn't very grateful to Barney for all his efforts to restore him to the throne, quickly becoming obsessed with the idea that his supporters would have preferred Leopold to die and Barney to become king.
- "Wanted!" Poster: One is distributed through Lutha after the king's escape, and the description on it is a recurring cause of people mistaking Barney for the king.
