Tintin and the Golden Fleece pendulum, Calculus insists that the gold is still right above them. Cutting away at the paint on the ship's railings Tintin realizes that they are in fact the camouflaged gold. The chest contained the real railings, and was just a red herring. Haddock finally returns the gold to Tetaragua. The main square in the capital is renamed Paparanic Square, and Haddock receives Tetaragua's highest decoration, the Order of the Scarlet Cheetah. Back home at Marlinspike Hall, Haddock hires Clodion as his cook, and Calculus keeps Romulus as a pet and a test subject for his inventions of a flying birdcage.
The Secret of the Unicorn Haddock was "the best realised character" in the story, conversely describing the Bird Brothers as "relatively uninspired villains". They went on to state that "The Secret of the Unicorn"-"Red Rackham's Treasure" arc represents "a turning point" for the series as it shifts the reader's attention from Tintin to Haddock, who has become "by far, the most interesting character". They praised the "truly outstanding storytelling" of "The Secret of the Unicorn", ultimately awarding it a rating of four out of five. Phillipe Goddin commented on the scene in the story in which Haddock relates the life of his ancestor, stating that