Red Rackham's Treasure

When Tintin and Captain Haddock set sail to find Red Rackham's treasure, Professor Calculus smuggles his miniature submarine aboard and stows away. They use the submarine to find the sunken ship, but find no treasure. Calculus directs them to an alternate site on shore, but still they find no treasure and return home disappointed. There Calculus discovers that Marlinspike is the Haddock family estate, and lends Captain Haddock money to buy it. There, at last, they find Red Rackham's treasure.