The duo have no idea what is going on. Calculus seems undisturbed, leaving the following day for Geneva, where he is to attend a conference on nuclear physics. All strange incidents seem to stop in his absence. It doesn't take long for Tintin to figure out the significance of this fact. The glass was breaking due to the Glass-Shattering Sound of a sonic weapon created by the Professor. Gunfights take place around Calculus because rival teams of spies, sent by the nations of Syldavia and Borduria, are tailing him, attempting to capture him and eliminate their opponents. Tintin and Haddock have to rush to Geneva and try to save their missing friend, but it might already be too late.
The album introduces Jolyon Wagg, an overly-friendly insurance agent, who invites himself into Marlinspike Hall during the thunderstorm and tries to sell insurance to Captain Haddock. He fails but has no intention of actually leaving. He even stays there while the residents are absent and soon invites his family for a joined vacation. The annoying man was based on a salesman who came to Hergé's door and invited himself in. The ever-annoying Wagg would become a recurring character.
- Adaptation Distillation: The animated adaptation removes the Syldavian agents from the story entirely. This streamlines the story by allowing it to focus on only one antagonistic faction (the Bordurians), while keeping most of the important plot points.
- Adapted Out: Jolyon Wagg in the Belvision version of the story.
- Bald of Evil: Sponsz.
- Beauty Equals Goodness: Tintin and Captain Haddock witness their friend Professor Calculus being carried off by mysterious figures, when another group ambushes them. When Haddock asks which side they should help, Tintin evokes this trope by telling him to hit the ugliest ones. Haddock is then confronted by two brawling mooks, each as ugly as the other. So he bangs their heads together. (As it turns out, the "rescuers" are trying to kidnap Calculus as well).
- Car Meets House: On driving a stolen tank to the Bordurian border, Tintin finds the road blocked by heavy trucks and the border protected by anti-tank obstacles. So he drives the tank straight through the guardhouse.
- Clingy MacGuffin: Parodied with the piece of sticking plaster. When Captain Haddock tosses it off, it sticks to someone else, who in turn shakes it off. And so it goes all over the bus, before coming to the Captain's cap. It then follows him aboard the plane, eventually makes its way to the cockpit (causing the pilots to momentarily lose control), lands on the Captain again by the end of the flight, is thrown away at the police station, only to return yet again on the captain's clothes in the hotel room!
- Commie Nazis: Borduria is depicted as a stereotypical half-Eastern Bloc and half-fascist country complete with its own secret police (ZEP) (led by Colonel Sponsz) and a fascist military dictator called Kûrvi-Tasch who promotes a Taschist ideology. A statue of Kûrvi-Tasch appears in front of a government building, in which he wears a moustache similar to Joseph Stalin's and gives a Nazi-like salute.
- Conspicuous Trenchcoat: Worn by the Bordurian spies.
- Continuity Nod: The book is filled with multiple references to the events of the Moon Books.
- Ditch the Bodyguards: Played With. While staying in Borduria as supposed "guests" of the state, Tintin and Haddock get their "bodyguards" drunk so that they can escape. Tintin even manages to get his locked in the Captain's room before the guard knocks to return the Captain's hat.I will be -hic!- very comfortably in the corridor -hic!- someone put a bed there...
- Double Take: Sponz' secretary tells his boss about the prison director who called to check about Calculus being moved. Sponz confirms that if his signature was on the papers, there was no need to call. Then he remembers the papers were in his coat, and goes to look for them...
- Dress-Coded for Your Convenience: During the story, a fight breaks out between the Syldavians, who are all wearing brown coats and have moustaches, and the Bordurians, who are all wearing grey coats and have shaved heads. The Captain doesn't know which side to aim for, so Tintin just tells him to go for the ugliest mugs.
- Drives Like Crazy: Arturo Benedetto Giovanni Giuseppe Pietro Arcangelo Alfredo Cartoffoli da Milano.
- Evil Counterpart: Well, evil is stretching it somewhat but Kronic and Klumsi are pretty much the Bordurian Thomson and Thompson, minus the physical similarity.
- Founder of the Kingdom: Marshal Kûrvi-Tasch is portrayed according to this trope in Bordurian propaganda.
- Hat Damage: Professor Calculus returns from his lab with a bullet hole going straight through his hat. He attributes the damage to moths.
- Hypocritical Humor
"There ought to be a law to make those infernal mileage-merchants stop when people signal."
- Haddock on hitchhiking, when he's the one out on the side of the road:
"Hitch-hikers! Blistering barnacles, there ought to be a law against them!"
- Haddock on hitchhiking, when he's the one comfortably inside an automobile:
- Earlier on, he chides Nestor for snapping at a woman who called thinking she'd reached Mr. Cutts the butcher. When the same woman calls later during a thunderstorm, Haddock snaps at her before he is catapulted into the chandelier by lightning.
- Men Are Uncultured: At one point, Tintin and Captain Haddock are hiding in the Klow opera. Tintin wakes the Captain up at the end with a disapproving Grande Dame looking on. Note that Hergé himself admitted to disliking opera, stating that it usually bored him or made him laugh (Bianca Castafiore was based on an opera-singing aunt of his).
- Nice Job Fixing It, Villain!: Sponsz boasts of his plans and the location where he has Calculus prisoner, unaware that Tintin and Haddock are hiding in the closet. He even mentions the release order for Calculus he has in his coat pocket, which has just been placed in said closet.
- No Swastikas: The book on Nazi secret weapons is an actual book...minus the swastika on the cover.
- Not So Different: Syldavia was previously portrayed as the good guys as opposed to the Bordurian villains. Here there's little or no difference, as shown in the Beauty Equals Goodness scene.
- Only a Model: The Bordurian military elite displays the effectiveness of a proposed new sound weapon through the destruction of a "large North American city" (an Expy of New York) on a TV screen to the delight of its audience, only to reveal that they had merely used a smaller scale version to destroy a model. Everyone is disappointed.
- Overly Long Name: Arturo Benedetto Giovanni Giuseppe Pietro Arcangelo Alfredo Cartoffoli da Milano, an Italian driver who helps Tintin and Haddock. He crosses the borders to France and gets pulled over for reckless driving. After giving his full name, the gendarme lets him off with a warning rather than bother to write it down.
- Punk in the Trunk: Subverted; Calculus is in a hidden compartment under the backseat, as Tintin realises far too late.
- Punny Name: Marshal Kûrvi-Tasch, noted for his curvy (mous)tache. It even appears on the Bordurian flag!
- Put Their Heads Together: Captain Haddock uses this move on two rival spies.
- Reliably Unreliable Guns: Our heroes are saved from certain death when an anti-tank gun explodes as it's about to blow up their stolen tank. They then run over some dud land mines.
- Reluctant Mad Scientist: Calculus invents a Nikola Tesla-style sonic superweapon. But he is extremely opposed to any government using his invention, goes to meet a fellow scientist because his discovery frightens him, and at the end burns the plans on his own volition. Meanwhile Syldavia and Borduria are all too eager to employ him and use the weapon on their enemies.
- Scale Model Destruction: Calculus' ultrasound device is used on a model of New York City. The results point to why both factions would like to use the device as a Weapon of Mass Destruction.
- "Shaggy Dog" Story: Both sides spend the whole book trying to kidnap Calculus not only for his knowledge, but because Calculus is carrying plans for his sonic device. At the end, Calculus unscrews his umbrella handle to find the plans are gone...then when they return to Marlinspike Hall, he finds he forgot to put them in there in the first place, and they were on his desk all along!
- Shown Their Work: Herge's drive for realism probably culminated in this album, where the amount detail put into background art and scene composition would have put a movie cinematographer to shame. In fact, in planning for a minor scene in the story where enemy spies force Tintin's car off the road into Lake Geneva, Herge actually sent a employee to drive along Lake Geneva to find a location where assassins might plausibly force a car off the road. Also the fire truck shown after the house explodes was the exact reproduction of the actual fire truck of the town, down to the NUMBER PLATE.
- Smoldering Shoes: Subverted. Tintin briefly believes Captain Haddock to have been vaporized after receiving a massive electric shock, but he's merely been launched into the overhead chandelier.
- Sudden Sequel Heel Syndrome: In the previous book, the Syldavians were responsible for launching a rocket to the moon, with the Bordurians trying to stop them. Here, they're trying to kidnap Calculus to work for them, same as the Bordurians.
- Third-Person Person: Jolyon Wagg when he starts vocalising his internal monologue as part of an annoying story.
- Train Escape: Subverted. Tintin pursues the villains. They try to use this trope on him. He manages to stay on their tail.
- Villainous Breakdown: Colonel Sponsz completely loses it when he realises that Calculus's release warrant has been stolen. The last we see of him is him frantically screaming into a phone ordering his troops to blow Tintin to pieces.
- Wicked Cultured: Sponz seems to enjoy the Castafiore's performance, even inviting her to sing for a private party.