Part 1: "Don't Give Up the Ship"
The show opens in the city of Duckburg, where Scrooge McDuck is swimming in his three cubic-acre vault of cash. He is forced to stop, though, by the realization that he is late for something. So, with a quick change out of his swimsuit and into his normal attire, he makes his way to the pier, where Donald Duck, now enlisted in the Navy, is preparing to ship out. As Scrooge arrives, Donald is saying goodbye to his nephews, Huey, Dewey and Louie, leaving them in the care of Scrooge while he's away. The boys are not very keen on staying with Scrooge for an indefinite period, and Scrooge is not keen about the idea either, but Scrooge is "the only one [Donald] trust[s]" with watching the kids.
After Donald leaves, Scrooge brings the boys to his mansion, where he introduces them (and the viewers) to Duckworth the Butler. The boys are forced to have their meals sent to them in the attic, and receive a letter from Donald about his "adventures" in the Navy. After reading the letter, the boys manage to get out of the attic to fool around the mansion before Scrooge decides to leave for his Money Bin. Duckworth has firm orders to not let the kids leave the mansion, but the boys tie him up with a curtain sash ("This is definitely going to delay dinner"). Scrooge reluctantly allows the trio to hang around his bin, provided they don't touch anything. Scrooge tries to get the boys off his mind by kicking out solicitors. Among them is the leader of the Junior Woodchucks, whose offer Scrooge shows interest in. Just then, the nephews get ahold of a small wooden ship in Scrooge's museum that they thought they could send to Donald. Infuriated, Scrooge has them grounded.
Meanwhile, three of the Beagle Boys - Big Time, Burger, and Bouncer manage to escape from jail using bombs that were sent to them disguised as bonbons. They then meet with El Capitan, the person who sent them the bombs, in the abandoned O'Lorange Theater. El Capitan, an anthropomorphic dog in a trench coat, arranged their escape because they are experts on Scrooge's Money Bin, and he wants them to steal a small wooden ship from it. The nephews, upset with Scrooge punishing them, decide to run away, but happen to notice El Capitan on the streets. They also notice the Beagle Boys in the Money Bin and run in to investigate. They fail to stop the Beagles from stealing the model ship, but the criminals end up leaving behind a map of Scrooge's Money Bin drawn on the back on a theater flyer. Scrooge comes in, having been awakened by the alarm; the boys try to explain what happened, but he refuses to believe them, thinking that the kids are the only ones who were interested in stealing the little boat.
Luckily, the nephews figure out that the theater advertised on the flyer is where the Beagles are hiding out, and, thanks to the Junior Woodchucks Guidebook, they construct a hang glider to get out of the attic. Afterwards, they head for the O'Lorange Theater, where they find El Capitan and the Beagles discussing the boat. According to El Capitan, it is actually a map that leads to a sunken treasure ship full of gold, and he is the only one who can interpret the code. The nephews nab the ship and escape, figuring that Scrooge will help them.
The Beagles chase the trio all the way to Scrooge's candy factory, where Scrooge himself is answering questions for an interview, which eventually causes him to admit that he's grown fond of those pesky nephews. The two trios crash in, and Scrooge's nephews explain what's going on. A food fight breaks out, which eventually results in the Beagle Boys being covered in chocolate and sent back to the jailhouse. Scrooge apologizes to his grandnephews for not believing them earlier, realizing that this odd map may have something deep to it. El Capitan, meanwhile, swears revenge.
Part 2: "Wrongway in Ronguay"
Huey, Dewey and Louie manage to decipher the code written on the map, but they refuse to tell it to Scrooge unless he allows them to join him on his treasure hunt. Just then, Flintheart Glomgold pays a visit, wanting to buy Scrooge's candy factory for $2,000,000. He makes a bet with Scrooge in which one of them must try to earn more cash than the other within two weeks. (The loser has to eat Glomgold's hat.) Scrooge agrees to this bet, and allows the boys to join him, since they know where the sunken treasure ship they're going after is - Ronguay, South America! Unbeknownst to the good guys, Glomgold is getting some help of his own from El Capitan.
The ducks take a cheap plane that they soon realize is going in the wrong direction. Upon realizing this, they storm the bridge and find out that the pilot is a cheaply-made robot from Glomgold's company; this raises Scrooge's suspicions. After landing in Ronguay, they are stampeded by fleeing citizens who take off in the plane. Scrooge gets some supplies and a llama from a nearby supply store, whose owner tells him that the Monsapis are coming. He and the nephews trek off into the desert, during which Scrooge almost sinks into some quicksand that he didn't see because the "Danger" sign was sawed off.
As Scrooge suspects, Glomgold is trying to sabotage the journey so that he and El Capitan can find the treasure ship first. They have an imprint of the map from Scrooge's chocolate, which they are keeping solid by way of an ice cream cart pulled by a pack mule. Glomgold throws some dynamite in Scrooge's direction, but when he and El Capitan turn around to discover that their pack mule has eaten their chocolate map, he is forced to snuff the fuse. At this point, the Monsapis, a centennial series of torrential rain and flooding, begin to occur, scaring off Scrooge's llama.
Scrooge and the nephews manage to find a cave that looks just like an upside-down ship, but they find nothing upon entering. They stop here to rest, but before doing so, the nephews set up a Junior Woodchuck alarm. When Glomgold and El Capitan show up, they set off the alarm, awakening Scrooge and the boys. Glomgold and El Capitan then manage to climb out of the flooding cave and try to trap the Scrooge and the nephews within. Fortunately, Scrooge and the nephews do not go much farther before they find what they've been looking for - a shipwreck full of gold. After repairing the ship and getting it out of the now-flooded Ronguay, it looks like smooth sailing until a gun-toting Glomgold and El Capitan spring out of hiding.
Glomgold gloats as he lowers Scrooge and the nephews into the sea on a life-boat. But Glomgold then makes the mistake of tossing one of the ship's many gold coins to Scrooge. El Capitan does not want to lose any of his gold and demands that Glomgold go out and bring it back. Their bickering results in the sinking of the ship, and Glomgold ends up being rescued by the nephews. Since Scrooge has won the bet by virtue of the aforementioned coin, Glomgold must eat his hat. The boys wonder what became of El Capitan, who again swears revenge.
Part 3: "Three Ducks of the Condor"
While the boys are scaring off nanny applicants, Scrooge shows the coin he got at the end of the last episode to a coin expert, who confirms it to be a coin from the Treasure of the Golden Suns, and tells Scrooge that there is another coin from this treasure over in a fortress in the Andes Mountains. Scrooge decides to go find the owner of this coin, but before he does that, he gives the job of the nephews' nanny to their most fearless applicant, Betina Beakley, who says she will work for nothing except room and board for her and her granddaughter, Webbigail Vanderquack. After this, Scrooge meets with Gyro Gearloose, who builds a flying machine called the Golden Condor. He calls up the only pilot capable of flying it - Launchpad McQuack. Additionally, Donald's crew is in Panama, and he's been given a three-day pass, so he can temporarily join Scrooge in this expedition. Huey, Dewey and Louie are quite peeved that they cannot come along.
After picking up Donald just as his break begins, the three ducks make a crash landing in the Andes. Launchpad feels proud of himself, but Scrooge orders him to climb down and find the plane. While he's doing that, Donald and Scrooge head off to meet the local antagonist - Joaquin Slowly, High Priest of the Golden Sun, who has a lot of people bowing down to him because he has a Sun Coin. The natives then start doing the same to Scrooge, since he also has a Sun Coin, much to Slowly's annoyance. Under demands by Scrooge, Slowly goes over his background, about how his ancestor, Marcheen Slowly, and his companion, Juan Tanamera, stole a boatload of treasure from the Valley of the Golden Suns. But the ship was then stolen by the ship's captain, who left them with one coin. The pair made a map to said valley and tore it in half. Marcheen happened upon these "Gold Sun!" chanters, while Juan wound up losing the other half of the map in Antarctica.
As he argues with Slowly, Scrooge sends Donald to go help Launchpad fix the plane. Launchpad, having reached the bottom of the cliff, has found the remains of the Golden Condor. He is then found by several more chanters, who want him to fly a real live condor. Donald, happening upon this ritual, helps Launchpad out by flashing his camera in the condor's eyes, allowing the pilot to take better control. Launchpad crashes the condor into the temple. Slowly resists giving Scrooge his half of the map, but reluctantly agrees to trade his half of the map for Scrooge's Sun Coin.
The next afternoon, the trade occurs, but just as Scrooge expects, Slowly tells all the "Children of the Sun" that he [Slowly] is the only High Priest, and that Scrooge is an impostor. A chase ensues, with the chanters flying real condors as they chase the three ducks in their 24-karat one. Eventually, the heroes escape, and the chanters crash into Slowly. Slowly ends up dropping his coins, and they fall off the cliff. He commands his harem to go down and get them, but they refuse to obey his order now that he has lost the coins. Scrooge jettisons the plane so he can ride the currents to Antarctica, where the other half of the map is, and Launchpad drops Donald off at his crew's ship.
Part 4: "Cold Duck"
Back at the mansion, Huey, Dewey and Louie are trying to annoy Mrs. Beakley and Webby by way of a tuning fork. Just when Mrs. Beakley is about to use it on them, Launchpad shows up outside, piloting Scrooge's cargo plane. As the pilot runs about, tossing everything crucial and non-crucial into the plane, Huey, Dewey and Louie, trying to avoid Webby tagging along, sneak into the plane, but she follows them there. Launchpad unknowingly takes off with the kids in the plane, and when a scarf-bearing Mrs. Beakley catches sight of Webby in one of the windows, she hitches a ride on the landing gear. Fortunately, Launchpad manages to get her inside before she can slip and fall to the sidewalk below. Mrs. Beakley demands that Launchpad turn the plane around and drop them back off at the mansion. The pilot refuses, because he has to get this stuff to Scrooge before his homing beeper dies.
The group lands in Antarctica, and before long run into a little girl penguin chased by a walrus who is toting Scrooge's homing beeper. Mrs. Beakley's scarf attracts the walrus like a red cape, and Launchpad ends up being dragged along. Huey, Dewey and Louie reluctantly try to save them. The nephews ponder why the walrus was wearing Scrooge's things, and then dismiss Webby's new penguin friend as "another tag-along." Fortunately, they go with Mrs. Beakley's idea of backtracking the walrus' tracks. They come upon a cave where Scrooge has left his mark. After slipping on a frozen river, Launchpad fires a flare gun that causes the river to break apart and send him and the nephews towards a waterfall. Fortunately, the males survive the waterfall, but they do not know where they are going. Behind, Webby and Mrs. Beakley realize they'll have to find them. Just then, the penguin girl, whose name is Skittles, speaks up, saying that because everything in Antarctica is white and/or grey, colored objects are treasured by penguins.
Shortly after arriving in the never-named underground city of the talking penguins, Launchpad and the trio are ambushed by the mayor and his goons, because they want their colorful clothes. Then, when Launchpad tells the top-hatted penguin mayor that he knows Scrooge McDuck like a brother, the penguins throw him and the boys into the local jailhouse. Fortunately, Huey finds out that Scrooge, also stripped of his colorful outfit, happens to be in the next-door cell. Scrooge explains that he found the other half of the map to the Valley over in the museum, but before he could get it, the penguins had arrested him and taken his half of the map. Scrooge is positive that there is still hope when he hears that "Mrs. Beakley's still wanderin' around", but the three nephews believe that "she'll be captured easier than we were."
Over at Skittles' house, Webby disguises herself as another penguin, and Mrs. Beakley goes off in search of everyone's clothes, leaving Webby and Skittles in the house - or so she thinks. Instead, the little girls head off to the Color Museum to discover that both halves of Scrooge's map are encased in the thickest ice possible. Mrs. Beakley, in the meantime, somehow finds the stolen clothes and pops up at the jailhouse. Huey, Dewey and Louie are a little grateful to her for bringing their clothes, and they are even more grateful when she reveals that she brought the tuning fork along. The boys use it to break free, destroying the jail in the process. Unfortunately, it also breaks out a gigantic walrus who had been frozen in ice.
While Launchpad goes to warm up the plane, Scrooge plans to use the tuning fork to get the map out of the ice once they get to the museum, provided they avert the snowball-throwing penguins first. Before reaching it, he and the boys come upon Webby and Skittles. The penguins run away, because the gigantic walrus then shows up and crushes the museum, along with Scrooge's hopes of getting the map out. The nephews run from the walrus as they try to get to the plane, and not far behind, Mrs. Beakley, Scrooge, Webby, and Skittles dash away from the bigger birds in town. The group soon ends up at the edge of an ice-cliff, with the walrus ready to clip their wings off. Suddenly, Launchpad flies in, scooping up the whole cliff point in the cargo plane, including the walrus. Before the walrus can sink his tusks into anyone, Scrooge smashes an alarm that sends the walrus plummeting into the ocean below. The boys thank Mrs. Beakley for saving them, and then Webby reveals that she managed to reproduce the map using her crayons. Skittles returns to her folks via colorful parachute, with Webby's crayons and Mrs. Beakley's scarf as parting gifts.
Part 5: "Too Much of a Gold Thing"
As he and his companions fly over the Wakka-Wakka River, Scrooge grows impatient, yelling at everyone and scratching himself like he has fleas. According to Mrs. Beakley, Scrooge has caught gold fever, a disease that causes its recipients to itch for gold so much they forget everything else. He orders Launchpad to speed up landing the plane, but when he does that, they find themselves being carried away with the current. Luckily, they avoid going over the waterfall on account of Launchpad opening the loading-bay doors. Scrooge, the trio, Webby, and Mrs. Beakley take a raft outwards, with Launchpad assigned to stay behind and get the plane floating again.
Before long, they run into an angry squadron of alligators, whom they manage to evade by puncturing the raft with a knife, thus propelling them away from the gators. They continue onward to the treasure, because there's a pathway leading there. Unbeknownst to any of them, though, El Capitan is not far behind. Meanwhile, Launchpad has to anchor the plane to the shore, shut the doors, and pump the water out. As he's trying to do that, he is attacked by a snake who tries to drag him underwater. He eventually manages to complete pumping the plane out.
After the nephews save Scrooge from a trap planted for anyone dumb enough to follow the suspicion-arousing pathway, Scrooge comes up to an escalator. By now, Scrooge's twitching is worse. Just when it looks like they've reached a dead end, Scrooge and the kids use a tree limb to open the invisible door. Inside is the Valley, where they stumble upon the first fraction of the treasure - a ring of giant golden discs. Just this much is even more gold than in Fort Knox, according to Scrooge, who tries to loosen one of them from the wall, believing he can carry it back to the plane. The disc does loosen, but it ends up falling down the walls, taking the gang with it. Luckily, they jump off at the right time, and the disc hits a hill-disguised temple made of gold.
Scrooge, whose gold fever is by now so bad that he's hiccuping and at one point acts like a cat, uncovers the entrance to the temple, where practically every room is made of gold and stocked full of it. They head inside the central chamber inside the temple and come upon skeletons of deceased explorers who'd also been infected by gold fever. Scrooge refuses to believe he will meet a similar end, and he does not believe the nearby well leads anywhere. Instead, he and the nephews (who are starting to catch gold fever themselves) explore the courtyard, seeing what this place has to offer. As the males check out the chambers of gold dust and gold coins (which, as noted by the nephews, looks identical to Scrooge's Money Bin), Webby tries to translate a "stone" tablet that says that that anyone greedy enough to open all the doors will set off another trap. Scrooge discovers this too late, unknowingly setting off the curse. He is knocked out by one of the gold bricks from the third room, and all the doors shut, trapping the ducks. To make matters worse, El Capitan then arrives, pointing a shotgun at them.
El Capitan makes them get into the pot hanging over the aforementioned well, claiming that he has been waiting 400 years for this, and begins to lower them into the so-called lava pit. Scrooge regains consciousness and begins shivering in spite of the intense heat, which is the final step in gold fever, because the lava is also made of gold. Scrooge declares this to be "the real Treasure of the Golden Suns", and upon hearing this, El Capitan brings them back up, saying he "won't have them tasting a single drop of [his] gold." Scrooge and El Capitan begin fighting, failing to notice the curse's effects. They temporarily stop in order to dodge the floor when they notice it is collapsing and jump to safety. Then the walls start moving, trying dump them all into the golden lava below. It is at this point that Scrooge finally snaps out of his gold fever and uses the vines growing on the walls to climb out with the rest of his group. They even take El Capitan with them, despite his urging to be left with "all the pretty gold". The curse next has the giant gold discs reflecting their light into the lava, causing a volcanic eruption. Launchpad notices this and, believing this to be a rescue flare that Scrooge would signal him for, gets the plane back up and running, and saves everyone.
Upon getting out of the destructing Valley, the heroes land back in the river, and El Capitan breaks loose. But when he comes to the spot where the Valley would be, it's now buried under a mountain of dirt. While Scrooge finds this hilarious, the frustrated yet undaunted El Capitan starts trying to dig up the gold. Scrooge heads back to the plane, saying that he wishes he had gotten at least one souvenir out of this. And it turns out he did - another one of the gold lava's eruptions gave the cargo plane a new paint job! Scrooge looks forward to relaxing, saying he's through with treasure hunting... or so he thinks.
Scrooge: What are you doing here?
Huey, Dewey and Louie: We missed ya, Unca Scrooge!
Launchpad: Well, the engines are busted, but those condors gave me an idea! Trouble is... I don't know how to get 'er off the ground.
Donald: You leave that to me!
El Captain: I've waited 400 years for this!
Mrs. Beakley: 400 years? You're mad!