The Old Castle's Secret is a Donald Duck story written by Carl Barks in June 1948.

Plot

Warning: Wikipedia contains spoilers

Scrooge McDuck, in his second appearance, recruits his nephews to search for a family treasure back in Dismal Downs, the old castle of the Clan McDuck, built in the middle of a swamp in Scotland.The treasure once belonged to Sir Quackly McDuck but both the treasure and its owner disappeared during the siege of 1057.The Clan has been searching for the treasure for centuries but Scrooge "The Last of the McDucks" believes that he can finally locate it thanks to an X-Ray machine that can look behind the castle's walls. Finding the treasure proves to be the easy part of the mission. But they have to face a mysterious "ghost" that steals the treasure from them and repeatedly tries to dispose of them. They can't see it but they can see its shadow, the shadow of a skeleton. At the end of the tale the ghost is revealed to be a thief using a formula that made him invisible but did not prevent his skeleton from casting a shadow.

Analysis

The story is usually referred to as one of Barks' most memorable for a number of reasons. The plot borrows elements of horror and mystery stories, favorites of Barks, such as the old and mostly abandoned castle with dark halls, hidden dungeons and crypts, ancestors' skeletons buried inside the castle, the old McDuck cemetery with the graves of entire generations of the main characters' ancestors, the misty swamp, the threatening "ghost" and the eminent danger that the characters feel around them. Barks put an effort into the details of every panel so that they gave a sense of melancholy suitable for this rather moody story and he used pictures of old Scottish castles as drawing references to add to the story's realism. It is considered among his best drawing efforts.

The story marks the second appearance of Scrooge in a story but the first where he acts as the leader in a treasure expedition, a theme that Barks would later use often and is currently considered traditional for an Uncle Scrooge story. It introduces the Clan McDuck, giving a family history to the characters that would later be expanded by both Barks and his "successors" and firmly setting the character's origin in Scotland, a homeland where a number of later stories would take place. Dismal Downs itself has been used as a setting for other stories and its history and architecture expanded.