Scrooge's cargo ship is sunk by a sea serpent, which goes on to eat Scrooge himself; meanwhile, the kids (including Webby) are doing some merit-badge-earning-type stuff. Naturally, the sea serpent is a human (well, avian) construction (there's a certain similarity to "Terror of the River"), and it must be stopped, Scrooge rescued, and merit badges earned.
I've gotta tell you, there's not much I liked about this episode, for two main reasons. First: there's the portrayal of the Woodchucks. For one thing, we have Launchpad as a troop leader again, which is so wrong-headed it drives me crazy. I don't like when the writers do stupid, lazy things just because it's easy. Also, they have an awful, horrific, intolerable chant where they go "Wacka-Wacka-Woodchuck." Whoever came up with that one should certainly be thrown off a steep embankment. Next, there's Webby. Now, I COULD just shout "HEY! The Junior Woodchucks are NOT coeducational! She should be in the Chickadee Patrol!" And, in fact, that's just what I'm going to do: HEY! The Junior Woodchucks are NOT coeducational! She should be in the Chickadee Patrol! Still, that's not my main concern, even though having her as part of a rival scouting group could provide some good story ideas. No, my problem is that she's presented as a beginner Woodchuck, and she outshines HDL and Doofus because they're just half-assing it, on the basis that they have enough Merit Badges already. Now look, I appreciate the feminist message and everything, but the idea of HDL as Woodchuck slackers is so fundamentally opposed to everything we know about their character the whole thing is just too ridiculous to take seriously. Gromph.
My second concern is that the plot just falls apart. There's a Black Pete character (not nearly as adorable as the one in "Pearl of Wisdom," sadly). When Scrooge's ship sinks, he takes possession of the cargo. The kind of thing that a bad guy is going to do, right? But then the "stolen cargo" plot is completely dropped and Pete, along with the also-shady Captain Mallard, become good guys and help to deal with the serpent. Making Pete behave against type is an interesting surprise, but the initial plot is never resolved, and in the end he just disappears and the show doesn't make even the most token effort to reconcile his earlier and later behavior. Please tell me that there's something I missed that would make this less poorly-plotted than it initially appears. Thanks.
-…and Doofus's crush on Launchpad is becoming somewhat creepily intense.
-"Captain Mallard and Dogface Pete seem pretty chummy."
"Like me and Launchpad?"
"Like Bonnie and Clyde!"
So what you're trying to tell me is, they're fucking. Come on--you can say it.