The 24th and final Tintin adventure, unfinished due to an unfortunate case of AuthorExistenceFailure.
An art craze sweeps over Europe - everyone is suddenly obsessed with Alph-Art, or statues of letters. Even the Captain buys an '''H''', but Tintin remains skeptical of the movement. He looks into Alph-Art's origins, and finds his usual mess of crooks and swindlers (including [[Recap/TintinTheSecretOfTheUnicorn Sakharine]], [[Recap/TintinTheBlueLotus Mr. Gibbons]], [[Recap/TintinTheBrokenEar Mr. Trickler]], and [[Recap/TintinLandOfBlackGold Emir Ben Kalish Ezab]]) using Alph-Art as a cover for forgeries. However, he is eventually caught, and Herge's last panel shows Tintin being marched away, to be covered with plasticine and sold off as a statue.
* ArabOilSheikh: Emir Ben Kalish Ezab uses his oil profits to negotiate the purchase of Windsor Castle and Centre Georges Pompidou, respectively landmarks of the United Kingdom and France.
* ArtShift: Unintentional, seeing that most of the story are loose drawings and sketches, intended to be redrawn later.
* DeliberatelyMonochrome: Subverted. The story is in black-and-white, because it is presented in unpublished form.
* DrinkOrder: Captain Haddock usually goes for Loch Lomond whiskey. In this story, Haddock can no longer drink due to the lingering effects of a pill used on him by Calculus. The withdrawal is causing him various problems and a change in lifestyle.
* HijackedByGanon: Tintin notes a few times that Endaddine Akass' voice sounds familiar. Following some draft of the author, it was about to be revealed that Akass is none other that Rastapopoulos who performed MagicPlasticSurgery. However what happened to him after ''Flight 714'' is a mystery.
* LeftHanging: The story ends with Tintin captured by a mysterious enemy. He is scheduled to be killed ... and there is no resolution.
** Yves Rodier made a finished version, which ends with Rastapopulos's on-screen death and Martine getting PromotedToLoveInterest.
* MadArtist: The story would have had Tintin encountering the modern art scene and becoming the focal point of one of these.
* NightmareSequence: Haddock has a nightmare involving Bianca Castafiore. At first it simply involves Bianca forcing him to drink 'his medicine". Said medicine is whisky, which Haddock can no longer drink without ill effects. He tries to resist and Bianca turns into a giant bird-like creature. She attacks him and the dream sequence ends.
* PunnyName: Endaddine Akkas's name is a pun of the Marol dialect expression ''En dat in àà kas!'' (''And that in your chest!'', said when telling someone off). Marol is a dialect spoken by Flemish people in Brussels.
* RealLifeWritesThePlot: Endaddine Akkas was based on the French art forger Fernand Legros and Ramo Nash on Elmyr de Hory.