While Captain Haddock and Tintin are walking through the country, they encounter a community camping in a landfill area. The two question them and after discovered that the community only chose the landfill area due to being prohibited by the police to use any other location in the area. Captain Haddock invites them to use the grounds of his estate, Marlinspike Hall, despite the doubts of his butler Nestor. Not long after that, Bianca Castafiore, the famous opera single, chose to invite herself to Marlinspike for a holiday, much to Haddock’s dismay. For some time before this, one of the marble steps in the foyer in Marlinspike Hall has had a dangerous plate-sized chip missing. Nestor has arranged its repair but has been waiting for the repairman to arrive. When he contacted the repairman Mr. Bolt he had merely fobbed Haddock off.Upon learning of Castafiore's imminent visit, Haddock hurries to pack for a trip to Italy, believing that now would be a good time to visit, because he had always avoided visiting the country in the past, specifically to avoid her. In his rush, Haddock misses the broken step, which, just moments before, he had been conceitedly warning Nestor and others about. He sprains his ankle as a consequence. A doctor arrives to examine the Captain and insists that the foot and ankle must be encased in a cast and imposes at least a fortnight's bed rest. As a result, the Captain has to use a wheelchair for a majority of the book’s remainder. The broken step then becomes a continuing source of comic relief for the rest of the story, and every main character, except Castafiore herself, slips and falls down the step at least once.
The Castafiore Emerald
Bianca then arrives bringing with her a sizeable amount of luggage, her entourage and a parrot, as a gift for the Captain, called "Iago." Just like the parrots encountered in Red Rackham's Treasure, the bird manages to pick up some of the Haddock’s slang, much to the Captain's annoyance. Haddock narrowly avoids having to share his study with Bianca and her piano, by managing to persuade her to locate the instrument, along with Igor Wagner, in a gallery. Wagner, it is later revealed, indulges a penchant for betting by making secretive runs into the local village to place bets. Adding to the Captain's problems, two over-zealous reporters from the Paris Flash newspaper, fabricate a story claiming that Haddock and Castafiore intend to marry, after a misunderstood discussion with the hard-of-hearing Professor Calculus. This leads to an avalanche of congratulatory notes from friends from all around the world. Subsequently, Captain Haddock himself learns to his horror the rumours of his alleged engagement spread by the tabloids. As a result he is forced to house an entire television crew, who reside in Marlinspike Hall for several hours while recording an extensive interview with his alleged fiancé.
The TV interview crew inside Marlinspike Hall.
A few days later, Castafiore's most prized possession, her emerald, goes missing, and all eyes turn to the Roma. The authorities search their encampment despite their claims of innocence. They are, however, vindicated when, in a deliberately anti-climactic dénouement, the culprit turns out to have been a thieving magpie. As soon as the emerald is found, it is (temporarily) lost once again by the detectives Thompson and Thomson, only to be seen still a few frames later by Snowy, who calls it a "brandyball," underlining the fact that the emerald is merely a device for the whole story to happen, and is in itself meaningless. Apart from the initial encounter with the Roma at the landfill, the story never leaves the confines of the Marlinspike estate, the story being decidedly domestic.