Scrooge buys an old castle with the intent to turn it into a luxury hotel. However, there are rumors the castle is haunted by the ghost of its former owner: Dr. Ludvig von Strangeduck. Not willing to let mere rumors cheat him out of a chance for profit, Scrooge opens the hotel and drafts his family as the serving staff. They soon get two guests; the wealthy aristocratic Duchess of Swansylvania and billionaire playboy racing driver Benzino Gasolini, but soon strange occurences start to happen that may make the world's richest duck reconsider whether to start believing in ghosts. Determined to find out what's happening, Scrooge and the nephews start following the guests, convinced one of them is behind the mysterious hauntings. Eventually they discover Dr. Strangeduck's walled-up laboratory and the Duchess reveals she came to the hotel to find out what happened to Strangeduck because she's really his sister. The next night, the ghost appears in her room and steals a box of jewels but then when it tries to flee, Scrooge reveals it to be Dr. Strangeduck's old lab assistant who'd sprayed himself with one of Strangeduck's inventions: invisibility paint. Then Ludvig von Strangeduck himself appears and reveals he was alive all the time. Brother and sister are reunited and decide to live together at the hotel with Scrooge marketing and selling Dr. Strangeduck's marvelous creations to the world.
This episode includes the following tropes:
- Billionaire Playboy: Benzino Gasolini.
- Clear Their Name: The Duchess wanted to "prove that [Dr. Strangeduck] was really a good boy" because she's his sister.
- Ditzy Genius: Dr. Strangeduck is an inventor that could give Gyro a run for his money but never thought to sell his incredible creations till Scrooge suggests it.
- Einstein Hair: Dr. Strangeduck has wild gray hair.
- Getting Crap Past the Radar: The Duchess has a lot more cleavage and a much lower cut dress than you'd expect from a Disney cartoon.
- Gratuitous Italian: Benzino Gasolini throws in Italian words to his sentences all the time.
- Haughty Help: As part of his preparations for turning the castle into a luxury hotel, Scrooge has Mrs. Beakley teach Huey, Dewey and Louie how to put on snooty airs as bellhops.
- Huge Girl, Tiny Guy: The Duchess is twice her brother's height even without her gravity-defying hair.
- Impossible Hourglass Figure: The Duchess.
- Invisible Villain: The Villain of the Week took one of Dr. Strangeduck's potions and cannot be seen until Scrooge undoes it.
- Mad Scientist: Dr. Strangeduck had a reputation for being one of these, complete with a Mad Scientist Laboratory
- Nonindicative Name: Scrooge comments upon finding the door at the bottom of the secret passage stairwell that it must be Dr. Strangeduck's "well-known secret lab."
- Nothing Is Scarier: A number of scenes during the ghost's haunting play up this trope before it's revealed he's just invisible. The scene in the bedroom where Mrs. Beakley and Webby place a sheet on a bed only to outline a person who isn't there is genuinely eerie, however.
- Red Herring: The Duchess is always snooping around and Benzino is never around when the ghost is, so the triplets suspect them. Neither of them was the ghost.
- "Scooby-Doo" Hoax: Strangeduck's assistant, Bruno was dressing up as a ghost to find something in the laboratory and steal people's valuables.
- Doing In the Wizard: Most of the ghost's activities can be easily explained once invisibility is invoked—presumably he was inside the suit of armor and statue which seemed to come to life, and leaped onto the table with the axe to chop it into pieces. But aside from the fact it's hard to believe an ugly bruiser like that could write flawless cursive when signing in as Dr. Strangeduck, exactly how did he make the books in the library fly around, and how did he appear as a skeleton shadow in the secret lab (and only that scene)? Hmmm...
- Shout-Out: The title is a reference to Dr. Strangelove.