At the start of the episode there is a baseball game going and the Junior Woodchucks team is down to the last out. Dewey is up for bat but the crowd keeps mistaking him for one of his other two brothers. When he tries to correct the people and tell who he really is it gives the other team the ability to pitch the ball and strike him out. After the game the boys return to Uncle Scrooge McDuck's manor house and they notice that Scrooge and Launchpad McQuack are looking at a map on the wall. Launchpad is holding a magnifying glass in one of his hands to see on the map where the kingdom of Montedumas is located at because it is so tiny. When Scrooge sees the boys come in hanging their heads because they lost the ball game he tries to cheer them up by telling them where they will be going. One of the boys asks about the kingdom. Scrooge then tells how he and the Count of Montedumas would spend hours in fencing matches and that they had a special handshake when the matches would be over.
The next morning, Launchpad has the helicopter ready. Scrooge, Huey and Louie are on board and the boys are wondering where their brother is at. Then the two of them see something coming towards them from a distance and they are wondering what it is until it gets close enough and they can tell it is Dewey wearing different clothing of sunglasses, strange hat, a bowtie, a polka-dotted shirt and a pair of green spats. Dewey then tells his brothers that he wants to have it to where people can tell them apart. Then when they get ready the helicopter takes off. As they are nearing the kingdom of Montedumas the engines are starting to stall and Launchpad tells Scrooge that the fuel lines are clogged. They all of a sudden start to crash and the people in the kingdom are running for their lives thinking the helicopter is a giant dragon. Then when Launchpad gets the helicopter to land only hitting a cart hauling chickens all of a sudden a man who has a patch on one eye comes up to them. That man is Captain Pietro and he starts issuing traffic citations and Scrooge demands to see Count Roy. When they are taken to the royal chambers and Scrooge thinks he is talking to his old friend the man they are really seeing is Ray the true count's double mint twin brother who has taken over the kingdom. He then tells Captain Pietro to have Scrooge and Launchpad taken to the prison tower and has the boys locked in what he calls "The Uninvited Guest Room". When Scrooge and Launchpad are put in the cell Pietro tells them "You are lucky you did not end up like The Duck in the Iron Mask!" Pietro leaves them laughing. At the same time the boys look out the window of the room they are in and see the tower that Scrooge and Launchpad are in. Dewey then comes up with an idea and takes off the crazy clothes he has been wearing over his normal blue shirt. He then suggests to his brothers to take their hats off. One of the others says "We really look alike without our hats. Then Dewey tells his brothers they just need to fool the guard. After the guard looks in and sees all three of them sitting on the floor waving at them Dewey then tells his brothers " Get those mirrors." They put three mirrors close together and he tells his brothers to use the rope and other items they found to climb up the chimney and get out to help their uncle. Huey and Louie ask him "What about you?" Dewey tells them that as long as he stays there in front of the mirrors and the guard thinks he sees three boys he will be fooled. Then Huey and Louie throw an item they have the rope attached to up the chimney and it catches on up top so they can climb out. Then when they get on the roof one of them is spooked by a gargoyle on the top of the building and causes both of them to start to fall down the roof and off the building. Fortunately the metal item that helped them get up the chimney with the rope catches onto the gargoyle and allows them to grab the rope and not fall all the way to the ground.
Huey and Louie carefully sneak around town and hide in a building when they see Captain Pietro coming collecting taxes. When Pietro knocks on the door of the firewood-chopping man demanding taxes he tells the wood chopper to either pay up or be locked in the tower with the Duck in the Iron Mask. Then Huey and Louie find clothing to put on that will allow them to look like local people. Meanwhile in the tower Scrooge is standing around telling Launchpad how he is wondering what has come over Count Roy. Then all of a sudden one of the stones between their cell and the next one is being pushed out of place and they start getting scared because the one pushing it is the Duck in the Iron Mask. Then when the masked duck climbs through the hole he calls out Scrooge's name and tells that he is Count Roy. Scrooge asks "How can you be him because he just put us in here?" The Masked Duck states "That was my evil twin brother Ray who has taken my place and locked me in this horrible mask. Scrooge then says "If you are Count Roy you will remember how we finished our fencing matches years ago." Scrooge then takes his cane like a fencing sword and taps the masked Duck in the chest and they do the handshake. Scrooge realizes that the Duck in the Iron Mask is his old friend the true Count of Montedumas. Then the three of them start hearing Huey and Louie calling out to Scrooge. Lauchpad and Count Roy ask Scrooge "How are we going to get the cell bars out of the way so we can get out the window?" Scrooge then says "The cement is old we can chip it away." Count Roy asks him "How?" Scrooge then tells him "Use your iron beak like a woodpecker and chip it away." Count Roy does that and after the bars are removed the three of them jump down into the hay wagon that the boys have backed up to the front of the tower. After they get away from the tower Count Roy scares the guard away from the door where Dewey is at. After Dewey is freed they then go to the room where Roy's brother Ray is sleeping on the chair at. Just as Roy is about to get the key from around his brother's neck Captain Pietro comes in there waking him up. A sword fight starts up and Huey, Dewey, and Louie throw to Launchpad, Scrooge and Count Roy three Fencing swords. Roy takes on his brother Ray, Scrooge takes on Captain Pietro, and Launchpad takes on the other two guys. As the fighting proceeds Roy corners his brother causing him to drop his sword. Roy then lifts the necklace Ray has around his neck off and takes the key to unlock the Iron Mask. Huey and his brothers help Launchpad by dropping a chandelier on the two guys he is fighting and then Scrooge defeats Pietro. Afterwards Count Roy has gotten himself cleaned up and is standing at the main gate of his kingdom and tells his brother Ray "Don't you ever come back here or I will make you The Duck in the Iron Pants!" Then as Scrooge hears the sounds of coins hitting the ground because Roy is returning the money to his people that his evil brother was taking from them with unjust taxes. Roy tells Scrooge that he has loaded the helicopter with Gold and other things he wants Scrooge to invest in McDuck Industries. As a gift to the boys for them helping their Uncle Scrooge and Launchpad get him out of the jail tower and defeat his brother he lets them have the clothing two of them used to sneak around town and gives Dewey one to match making them look like The Three Musketeers. As The show ends the Helicopter Takes off heading back to Duckburg.
- DuckTales: Volume 3