Happening upon a briefcase lost in the park Tintin returns it to its owner [[AbsentMindedProfessor Professor Hector Alembick]], an expert in sigillography (the study of seals - the ones on letters rather than the ones with flippers). Professor Alembick is travelling to the Balkan kingdom of [[{{Ruritania}} Syldavia]] and offers Tintin a job as his assistant. Tintin declines but later finds himself under surveillance by sinister individuals who seem connected with that country. After more than one attempt on his life Tintin decides to accept Alembick's offer and accompany him to Syldavia and get to the bottom of things.

Tintin soon finds himself thrust into the middle of a ruthless conspiracy to overthrow King Muskar XII of Syldavia in the interests of their fascist neighbor Borduria. Faced with traitors at every turn, Tintin has to race against time to save the King's throne. If the stolen King Ottokar's Sceptre is not returned by St. Vladimir's Day, the King will have to abdicate and the Bordurians will invade...

''King Ottokar's Sceptre'' was written in 1938 and 1939 and was written in the light of the threat of fascism; the Bordurian plot has parallels with Anschluss of Austria and Syldavia's location is reminiscent of Albania (invaded by Mussolini in 1939). Both Syldavia and Borduria would play important roles in later adventures and the story also introduced the recurring characters of Bianca Castafiore and the villainous Colonel Boris Jorgen.

* ANaziByAnyOtherName: The Bordurians - though they also have elements of other 1930's fascists.
* AsideGlance: Tintin actually winks to the reader on the last page.
* BlackShirt: Almost literally.
* DinosaurDoggieBone: Snowy steals a bone from a dinosaur skeleton at a museum.
* DoesThisRemindYouOfAnything: The [[TheGhost unseen]] leader of the consiracy is named [[BenitoMussolini Müss]][[AdolfHitler tler]].
* EasyAmnesia: The Syldavian spy at Tintin's house.
* EvilChancellor: Colonel Boris.
* [[spoiler: EvilTwin]]
* TheGoodKing: King Muskar XII is clearly devoted to his people, and is even willing to abdicate rather than try and keep power through bloodshed. [[spoiler: Fortunately Tintin manages to defeat the conspiracy and save his throne.]]
* GorgeousPeriodDress: The uniforms of the Sydavian royal guards.
* LockedRoomMystery: How was the Sceptre stolen?
* MeaningfulName: Averted with Professor Alembick, unlike most scientist Punny Names in Tintin--an alembic(k) is a piece of alchemical/chemistry apparatus, while Alembick is a Sigillographer.
* OutOfCharacterMoment: When Tintin meets Professor Alembick at the start, he's constantly smoking. He doesn't smoke at all for the rest of the book, which Tintin notes. [[spoiler:This is a clue that he's been replaced by an impostor]]. It's the other way around in the animated version where he suddenly starts smoking.
* TheQuisling / TheMole / DoubleAgent: A disturbing number of Syldavians are in Bordurian pay.
* ParanoiaFuel: [[InvokedTrope It seems like]] Tintin can trust no one in Syldavia and at one point even begins to wonder if even Professor Alembick has been replaced by an imposter. [[spoiler: He has.]]
* RedAlert: What the King essentially orders nationwide when Tintin warns him of Borduria's plans to invade.
* RoyalsWhoActuallyDoSomething: King Muskar XII drives his own car and knows how to use a gun to protect himself.
* {{Ruritania}}: Syldavia and Borduria. Syldavia in particular is often ranked as one of Hergé's greatest achievements - an extremely detailed and well researched fictional nation with it's own history, flag and language.