Louie teams with Goldie to scam their way through Doofus' dangerous party. Meanwhile, Huey pushes himself out of his comfort zone in his favorite online game.
One seemingly relaxing day at McDuck Manor, Scrooge going through his jewels senses something is amiss. In Webby's quarters, she, Lena and Violet are fighting a large werewolf; in the kitchen, Dewey and Beakley are having issues with a literal "tempest in a teapot"; in the living room, Della and Huey are starting up a video game called Legends of Legend Quest Dereznaroth wearing cosplay. Scrooge dismisses all of these as not concerning as he returns to his office. To his surprise, he finds Goldie in his office on invitation from Louie to be Louie's business partner.
In the hallway, Louie tells Scrooge that working hard to make money doesn't work for him. As Scrooge foils Goldie's attempts to steal from him, he warns Louie about Goldie's purloining self. Despite Louie's reassurances, Louie finds himself thrown into his own treasure chest as Goldie rifles through his stuff and pockets an idol and a bag of money. Louie attempts to win over Goldie by insisting he's the "evilest" of the triplets, then tries to evoke sympathy by tearfully admitting that Louie Inc. is his business dream, and Louie turned to Goldie for inspiration because everyone looks down on him. Goldie easily sees through Louie's attempt, but the green-shirted triplet's knowledge of cons convinces her to stay. She promises Louie to teach him what she knows, in return for sneaking into Doofus Drake's Septleventh Birth Anniversary party, much to Louie's protest.
Having started up the game in the living room, Della says that years back, she played the game after coming home from adventures while Donald and Scrooge opted to sleep instead. In the game, Della materializes with Mobile Suit-like armor and a scouter while Huey is in farmer's getup. To Della's dismay, Huey's idea of "epic" involves tending to his in-game garden behind a protective shield. While Della suggests quests such as raiding the Cybertroll Citadel and rescuing a princess from a heart-throbbing goblin, Huey kills some Grindhoppers trying to eat his crops and gains 3 experience points for each one, claiming he has to keep the crops safe so the in-game village can have turnips that season.
Meanwhile at Doofus Drake's house, Doofus has gathered rich families such as the Beagles and Mark Beaks and a small child of his. Louie and Goldie arrive like an aunt and nephew couple. While Louie is disgusted by a Beagle getting a mouth of splinters from a bobbing game and a cake suspiciously marked as "not full of hair", he spots a table holding gift bags of valuables which he and Goldie value at 457,000,000 dollars and 17 cents. Doofus's mother warns the two that the bags contain mostly heirlooms from the late Francis Drake and are only to be taken by guests leaving the party. When Mr. and Mrs. Drake prepare for Doofus's appearance, Louie tries to leave with two of the bags, but Goldie sets the bags back. Louie is exasperated, reminding Goldie of her plan to pretend to be family and leave with their gift bags, but Goldie explains that to do so would be too simple. Her real plan is to leave with all the bags, and she admits to keeping Louie out of the loop partly because he "wouldn't learn anything otherwise"; partly because she hasn't figured out the whole plan yet.
Just then, Mr. Drake announces Doofus's presence with an elaborate performance, only for the latter appears behind Louie. Doofus expresses his thanks to the families attending as the kinship reminds him of his grandmother, but he also suspects liars are present to steal his gift bags. Doofus first spots Percival P. Peppington trying to pass one of the Ottoman Empire stars Johnny for his son. Percival tries to excuse himself, claiming to have left his own real son in the car, but is dropped into a honey bin full of bees before Doofus ejects Johnny and the Beagle Boys posing as family members. The only guest families remaining are Louie's, Beaks', and Glomgold's, the latter having brought along a ventriloquist's puppet to pass off as his son. Doofus inspects Glomgold, and allows him to stay as he considers Glomgold's act with his "son" soothing.
Louie and Goldie rationalize that if they expose the others as frauds, they can make off with all the gift bags. Louie introduces Goldie as his "aunt" to Beaks, while Beaks introduces them to his son, Boyd. Mark Beaks shows off a number of photos such as the duo visiting a punk rock concert, the Lester Possum Park and the Duckburg Aquarium. Glomgold shows his own photos with him and his "son" dancing in different outfits.
When Doofus asks for Goldie's photos of her nephew, Louie goes into a nearby photo booth to snap a few pictures while Goldie stalls for time. At the last minute Louie manages to place the photos in Goldie's purse, which she shows to Doofus and convinces him of their legitimacy. After Doofus declares a swim in the pool, Goldie congratulates Louie on his quick thinking and suggests finding someone to mark for ejection from the party; upon noticing Glomgold ordering his "son" Sharkbomb to swim and arguing with his puppet, the two immediately decide to go for Glomgold first.
Back in the game, Huey does not want Della ruining the crops with over-watering when a checkpoint appears out of nowhere. Della explains that by cashing in experience points, one can begin grinding levels and unlocking loot. Huey points out that if his avatar is killed outside the shield, it would cost him all the experience points he accumulated. Della is astounded at the sheer amount Huey stored from protecting his garden. Just then, Launchpad's avatar arrives trying to slay a dragon. Della wants to help out despite her bad blood with Launchpad in the real world, but Huey declines her invitation. Della blasts the dragon out of the sky with her arm laser cannon, granting her and Launchpad XP which they cash in for new jetpacks as Huey watches on wistfully.
Back at the party, Doofus swims while Louie chats with Sharkbomb about Goldie having the hots for Flintheart. Predictably, this gets Flintheart's attention and causes him gets into a fight with his dummy son. As Glomgold brawls with his puppet, he ends up tearing off Sharkbomb's head, exposing himself as a fraud. Glomgold is thus ejected from the party. Louie and Goldie smirk at their success until Boyd rams them out of the pool with a shove.
In the game's world, Huey has continues to tend his garden while Della fights goblins. Finally tempted, he tells Della that he's considering venturing outside his comfort zone. After Della reassures him that she'll be there for him, Huey lowers the barrier to head for the checkpoint, only for a large flying monster show up and wrecks the crops.
While Boyd has fun at the party playing pinball, Goldie questions Louie about Boyd's weaknesses. Louie admits he hasn't been able to find any as he checks for Boyd's baby photos. The two notice the phone detecting a network called B.O.Y.D. (Beaks Optimistic Youth Droid). Realizing that Beaks would have posted his son's baby photos for the social media attention, coupled with the B.O.Y.D. network, Louie deduces that Boyd is a robot designed to be the perfect son. Goldie is concerned how they can outwit a robot designed to be perfect, but Louie assures her that he's an expert at dealing with robots.
To wit, Louie strikes a conversation with Boyd, asking the kid about what he did two days prior and when his birthday is. As he only came into existence a day ago, the logic bomb causes Boyd to realize he's a robot and not a real boy, prompting him to go on a killer robot rampage, wrecking the party and falling into the pool, shorting out. Beaks is thus ejected from the party by an angry Doofus. Impressed, Goldie offers permanent partnership to Louie until Doofus demands to know who's responsible for the incident.
Before Louie can think of an answer, Goldie points to him in accusation, then
reprimands Louie for wrecking Doofus's party and wanting the gift bags for himself, playing the role of a disapproving aunt. Louie privately calls her out on this, and Goldie freely admits that she never wanted a partner; she plans to send Louie home so she can steal the bags herself. However, Doofus has seized Beaks's cellphone with B.O.Y.D.'s controls and controls the android boy to kill Louie. The green-shirted triplet tries to escape, but B.O.Y.D. binds him with rope and pulls Louie up like a pinata. Surprised, Goldie asks Doofus what he intends to do, and Doofus explains he plans to treat Louie like an actual pinata, since he's a champion at whacking pinatas. With Louie strung up, B.O.Y.D. takes a baseball bat and moves in to bludgeon Louie, much to Goldie's horror.
Torn between stealing the bags and saving Louie, Goldie ends up stepping in front of B.O.Y.D. to get him to stop. To her and Louie's surprise, B.O.Y.D. shuts down and Doofus praises Louie and Goldie for passing the test. The whole ordeal was a test devised by Doofus to test their bonds of parenthood, just so Doofus could claim Goldie as his new "Goldiemama". Doofus relinquishes the gift bags to Louie and catapults him out.
Back in the game, Huey wails over the loss of his crops while Della attempts to fight the monster. As Della struggles against its tentacles, Huey realizes he isn't strong enough to help unless he cashes in his XP. Determined, Huey gets to the checkpoint and levels up so quickly, an astounded Della notices his power level is "Over 9000". Having attained Super Saiyan-like powers, Huey goes on the offensive against the monster.
Outside Doofus's house, Louie lands safely and revels in his victory, but is conflicted over leaving Goldie to her fate despite her earlier betrayal. Inside the house, Goldie has been encased in a glass prison and is forced to tell Doofus a story; she tells of an adventure where dimensional imps jabbed her with splinters and taunted her over greatest failures, but she considers being stuck as Doofus's "Goldiemama" to be far worse. Doofus asks for another story, but Louie returns with the prize bags, demanding Goldie's safe return. Doofus orders his parent slaves to attack, only for B.O.Y.D. to show up and surprisingly, frees Goldie from the glass prison with his laser eyes. Louie reveals that Doofus accidentally left B.O.Y.D.'s control unit in the gift bags, allowing him to take control of B.O.Y.D.. Addressing Doofus's parents, Louie suggests that his enemy should have no need for a "gummymama", but instead someone his own age to get close to. Louie then reappropriates B.O.Y.D.'s settings to treat the Drakes as his parents; the two Drakes happily embrace their new adoptive son.
Feeling betrayed, Doofus throws a tantrum and threatens to sever his parents's pay, but B.O.Y.D. transfers half of Doofus's inheritance to his own bank account, which he generously shares with his new parents. Now reassured by a truly loving son, Mrs. Drake sternly informs Doofus that he is to be grounded indefinitely, for which Doofus vows revenge at Louie. Louie remarks that when one gets close to another, they will feel like a family, similar to his own relationship with Goldie. However, he realizes that Goldie has already departed with the gift bags, leaving him with nothing.
In the game world, Huey destroys the monster which wrecked his crops in a bloodthirsty rampage, having gone so wild with vengeance Della has to physically pull him away from the game console, pleading with her son that he's "gone in too deep". Separately, Louie wails over how he's "gone in too deep", having invested in his partnership with Goldie without any easy money to show for it. Scrooge, amused, comforts Louie by explaining that "when one spends time looking for angles, it's hard to see what's in front of them"; con artists like Goldie are so obsessed with conning others they end up neglecting the relationships they form with others. Louie is still confused why Goldie saved him from Doofus, to which Scrooge suggests that just as Louie came to value his partnership with Goldie, Goldie cherished the bond they shared to a degree.
Outside, Goldie adds the photo of Louie to her wallet next to Scrooge's with a wistful sigh before walking off into the distance, with the gift bags stolen from Doofus's party slung over her shoulder.
Lester Possum Park from A Goofy Movie, Destiny from Finding Dory, and Flounder from The Little Mermaid make cameo appearances in some of Mark Beaks' cellphone pictures.
Legends of Legend Quest Dereznaroth seems to be based on the popular Blizzard computer game World of Warcraft.
Della describes Huey's power level as "over 9,000!" This is a reference to the popular internet meme, inspired by an infamous localization error from the anime Dragon Ball Z.
The revelation of B.O.Y.D. being a robot references the Star Trek The Original Series episode The Requiem for Methuselah when the seemingly human girl Rayna Kapec turns out to be an android created by the seemingly immortal Flint.
The most famous line from the film, The Most Dangerous Game is quoted by Doofus at one point in the episode.
BOYD after emerging from Doofus' pool ends up uncontrollably firing lasers from his eyes whilst moving around. This likely references what Jack-Jack had done pretty frequently in Incredibles 2.