Captain Haddock home, Marlinspike Hall (or "Moulinsart" in the original French). Harry Thompson, author of "Tintin: Hergé and his creation", writes that the introduction of this large and luxurious country house was "to provide a suitable ancestral home for Tintin and himself to move into." To achieve this in terms of the plot, Hergé also details Haddock's ancestry, something Thompson regards as distinctive: "Haddock is the only regular character whose relatives turn up in the Tintin stories at all (if one discounts Jolyon Wagg and his dreadful family)." As Haddock's role grew, Hergé expanded his character, basing him upon aspects of friends,
Tintin and the Lake of Sharks his every move), and the Captain and the detectives play a game of golf, Snowy runs into a frogman who has obtained from Madame Black some plans stolen from Calculus' laboratory. The frogman escapes by jumping into the lake, but Snowy manages to bite off a part of one of his flippers. After the Captain and the detectives tell Tintin what has happened, he gives the dogs the bitten-off flipper to sniff. While Gustav leads Haddock to a pile of abandoned tires, Tintin follows Snowy to a buried chain which, when pulled, opens a passage to a hidden cave where