Scrooge and Glomgold compete in a contest where the winner, being the world's richest duck, becomes the sales broker for a new fruit from Macaroon that works like a flashlight. First, though, Scrooge must keep his fortune away from the Beagle Boys. Next, as Scrooge tries to deliver his fortune to Macaroon, he experiences an interference in the form of a rogue Navy super-submarine working for Glomgold but Donald is there to help his uncle reclaim his fortune. After dumping his fortune under the sea, Scrooge, along with Launchpad, Gyro, and Doofus, submerges in order to get it out. There they encounter an underwater race of mermen, and a monster named Glubbzilla. Finally, Glomgold and the Beagle Boys attempt to make sure Scrooge doesn't win the contest on his way to Macaroon.
This episode contains examples of the following tropes:
- An Aesop: "Aqua Ducks" features the moral that you shouldn't underestimate your friends, as every one of them has talents that can be important.
- Animal Mecha: The navy's new sub is in the shape of a killer whale for the purpose of making it maneuverable underwater.
- Beyond the Impossible: The ice maker spewing coins is one thing, since at least it could be said to be connected to the water line, but why would an OVEN be connected to the water pipes at all?
- Bigger on the Inside: The box the three Beagle Boys arrive in is barely large enough to hold Big Time, the smallest one, but somehow all three Beagle Boys climb out of it.
- Chekhov's Gun: Gyro's Super Fizz drink becomes very useful in helping to get back to the surface.
- Crippling Overspecialization: Big Time's armored assault suit is able to withstand a 60 millimeter shell, but Scrooge has a tank that fires 61 millimeter shells, which Big Time realizes is one millimeter too many.
- Disappointed in You: Scrooge was not pleased at all when the nephews abandon the cloud machine hiding Atlantis in the sky.
- Dude, Where's My Reward?: Played with. When Doofus is rewarding Squeaker and the other dolphins for helping, Launchpad, who did most of the work, cries, "Hey, me too! Fishies!".
- "Everybody Laughs" Ending: The ending of "A Whale of a Bad Time," which has the entire cast cast bursting into laughter at Mrs. Beakley's pun, including the entire navy.
- Explain, Explain... Oh, Crap!: Inverted. When Scrooge's group is escaping to the surface on Atlantis, the mermen curse them and tell them to come back...until they realize they're taking all the trash on Atlantis with them, and they show gratitude.
- Fantastic Racism: The mermen view all "air-breathers" with contempt, viewing them as inferior beings who pollute their paradise with garbage. At least some of them even extend this sentiment toward dolphins.
- Fish People: With green skin.
- Floorboard Failure: This happened to the Grand Kiska of Macaroon when he was going downstairs for a midnight snack, resulting in him discovering firefly fruit.
- Get A Hold Of Yourself Man: When Scrooge's anxiety about the Beagle Boy situation gets to him, Dewey throws some money at his head. This succeeds in snapping him out of it.
- Gonna Need More X: After blasting Big Time out of the Money Bin, Scrooge patched up the hole he left with bricks. When Scrooge's giant cannon backfired and blew a big hole in the wall, Scrooge commented he was going to need more bricks as he saw the beagles coming up to the Money Bin with a ladder.
- Green Aesop: "Aqua Ducks" has one about dumping garbage in the ocean. Scrooge and company get in trouble with the mermen who live on the ocean floor because so much garbage has been dumped there. They part on relatively good terms when the ducks take a lot of it with them during their escape.
- Heat Wave: "A Whale of a Bad Time" starts with Huey, Dewey and Louie complaining about a heat wave and a broken air conditioner.
- Hollywood Density: Glomgold cheats by hiding lead weights in his pile of gold, however, gold is almost twice as heavy as lead, and much heavier than the metal coins are made of, so exchanging coins for gold bars would have been much more effective at increasing the weight of his money.
- Multi-Part Episode: Four parts in total:
- Part 1: A Drain on the Economy
- Part 2: A Whale of a Bad Time
- Part 3: Aqua Ducks
- Part 4: Working For Scales
- Offscreen Moment of Awesome: At the end of "Aqua Ducks", Atlantis is floating in the ocean with an upside down cruise ship balanced on top. At the start of the next episode, the cruise ship is gone and the island the city is sitting on is flying through the air suspended by balloons. Even though Aqua Ducks sets this up, we never get a payoff from this, and the next episode treats it as if this is no surprise to the viewer. The propulsion and cloud machine aren't set up at all, either.
- Out-of-Character Moment: Scrooge is rather cavalier about dumping his entire fortune down the Mariana trench rather than wait for the professor to fix the submarine, brushing it off with "Gyro will think of something".
- Overly Long Gag: Scrooge's Freak Out in "A Whale of a Bad Time", where he jumps around the kitchen repeatedly shouting "A sea monster ate my ice cream!"
- Plot Hole: The fourth episode segues into the nephews finding a clue to the fabled lost treasure of Atlantis, without any setup whatsoever explaining about what happened up to that point (having not appeared at all in the previous episode either). Combined with the offscreen moment of awesome mentioned above, it feels like there is a whole chunk of the story missing between episode three and four.
- Punny Title: The title is a variation on "catch as catch can."
- Right Behind Me: A variation when Bluebottle searches the security cameras for Scrooge and Donald. When he spots them, the camera shows they're right behind his chair.
- Sewer Gator: While searching the sewers in "A Drain On The Economy", the Beagle Boys dress up as a gator to frighten off the nephews. Then the Beagle Boys run into a real sewer gator.Louie: Uh, is it true that alligators live in the sewers?
Huey: Well, according to the Junior Woodchuck Guidebook-Aah! - Shout-Out:
- When the Beagle Boys successfully get past Scrooge's traps and reach the Money Bin, Huey comments "They're heeere".
- Encouraging the dolphin he's riding to speed up, Launchpad tells it he needs "warp speed."
- Surrounded by Idiots: A rarer heroic example; Scrooge McDuck is preparing to retrieve his vast fortune from the Marinaras Trench. He sees Doofus, Launchpad, and Gyro Gearloose, the crew that will help him, trip each other up and fall all over the place. And so, Scrooge can't help but exclaim in exasperation, "MORONS! I've got MORONS on my team!!"
- Toon Physics: This four parter seems to crank up the level of cartoony physics much higher than other Ducktales episodes, which tend much more to realism overall. This is most notable with the pile of Scrooge's gold, which acts as a single unit a lot of the time and doesn't seem to have much mass at all, despite being three cubic acres of gold.
- Use Your Head: Donald finds the controls to Bluebottle's supersub, the Moby 2 (which was used to steal Scrooge's fortune at sea thanks to Bluebottle hired by Glomgold). When Donald asks what to do, Scrooge tells him this. Needless to say, Donald uses his head to bash in the controls, prompting Scrooge to go, "So that's how he exercises his mind."
- Who Would Be Stupid Enough?: Launchpad inadvertently invokes this on himself; after Gyro has come up with a plan to help Scrooge, which requires someone to spread a concoction of his all over the sea floor, in spite of the fact that they're in the land of a group of hostile mermen. Launchpad asks who he thinks will be stupid enough to do that; one scene change later, Gyro and Doofus are helping Launchpad get situated on the dolphin he's supposed to ride for the stunt.
- Writers Have No Sense of Scale:
- When the money bin cracks, Scrooge's three cubic acres of money is somehow all flushed through a standard size sewer, which should be impossible in such a short time, let alone without clogging the drain. When the nephews finally find the money, its a rather tiny pile of money bags, certainly not the huge pile of cash usually in the money bin.
- The Beagle Boys somehow manage to climb to a high window in the money bin with a ladder that can't be longer than a few meters. This is mostly done through false perspective and jump cuts.
