While trekking through the desert, Haddock hallucinates and remembers his ancestor, Sir Francis Haddock, the 17th-century captain of the Unicorn whose treasure-laden ship was attacked by the crew of a pirate ship, led by Red Rackham, later revealed to be Sakharine's ancestor. Sir Francis surrendered and eventually sank the Unicorn and most of the treasure, to prevent it from falling into Rackham's hands. The story implies there were three Unicorn models, each containing a scroll; together, the scrolls can reveal coordinates of the location of the sunken Unicorn and its treasure.
