French gentleman Arpin Lusène, notorious for his secret identity as Le Chevalier Noir ("The Black Knight"), the world's greatest cat burglar, comes to Duckburg to test his skills against Scrooge's Money Bin.

None of Scrooge's security measures are able to stop the Black Knight, as the solvent instantly dissolves everything in its path, including bullets.

When the Black Knight reaches the door of the vault, Scrooge challenges that he won't be able to steal all of McDuck's money at once.

Desperate, Scrooge realizes how to defeat him: by pulling a rug out from under his feet and tipping him onto his back, where he falls down through the many floors of the bin.

Luckily for the Black Knight, his fall is broken by the contents of Scrooge's diamond vault, and the impact knocks him senseless.