The Duck family travels to the eastern city of Macaw to see the fabled Golden Cricket and visit Donald's cousin Gladstone Gander, the world's luckiest duck. While Scrooge McDuck is keen on seeing the cricket, the kids are excited to visit Gladstone; Scrooge and Donald, however are not. Donald had been jealous of his luck ever since he and Gladstone were young, while Scrooge dislikes Gladstone for his constant dependence on supernatural luck. The group find Gladstone is residing at the House of Fortune, a massive hotel/casino. While Scrooge and the others visit the casino, Launchpad stays behind to attend to personal matters. On his end, after making a sloppy but safe landing in the water, Launchpad leaves to meet with Ziyi.
Inside the casino, Gladstone welcomes his family, impressing the kids much to Donald's dismay. When Gladstone asks them to stay for a bit, Scrooge decides to leave with Huey, Dewey and Webby, but Louie and a reluctant Donald decide to spend time with Gladstone. Gladstone uses his luck to earn winnings as Louie becomes more and more fascinated by Gladstone's ability. As Louie enjoys the prizes Gladstone earns, Donald gets the short end of the stick with his bad luck, becoming increasingly downtrodden over how Louie admires Gladstone as the favorite uncle. Meanwhile, Scrooge's group is greeted by Toad Liu Hai , the casino's owner. Liu Hai encourages the group to stay and enjoy the casino; Scrooge declines at first, but ends up spending time there when the kids get enticed by the casino's luxuries. Scrooge continues to search for the exit, but somehow they keep moving in circles.
Eventually, Scrooge gives in and agrees to check in the casino. Liu Hai leads them to the front desk to reserve a room, but it turns out that Scrooge tricked him to leading the group to the exit, which is nearby. Before they can leave, Donald gets fed up with the praise Gladstone receives from Louie and decides to leave the casino with them. Gladstone tries to stop him, and it is revealed that Gladstone has been mystically imprisoned by Liu Hai. Liu Hai then reveals his true nature: he is a spirit of fortune and the entire casino is an illusion, a trap to lure the greedy.
Gladstone admits that because of his luck, Liu Hai imprisoned him to feed on his fortune and grow stronger. He called Scrooge and Donald to rescue him in the first place, but couldn't tell them to hide suspicion from Liu Hai. Liu Hai then proposes that Scrooge take Gladstone's place, as the richest duck in the world is more valuable than someone who just happens to be lucky. Instead, Scrooge challenges Liu Hai to a game for their freedom, which an intrigued Liu Hai acepts; however, Gladstone is chosen as Liu Hai's champion with Donald to represent the Duck family, and the game is a race to the finish line. Gladstone is able to avoid the race's obstacles with ease, while Donald continuously faces the traps and strays behind. When Donald is about to give up, Louie encourages him to keep going; motivated by their support and remembering his tenacity, Donald is able to make it ahead and crosses before Gladstone (who ironically was distracted by a twenty dollar bill in front of him).
Although Donald won, Scrooge convinces Liu Hai to take Donald as his prisoner instead of Gladstone. The group is released, but the kids, including Gladstone, are furious at Scrooge; however, Liu Hai is severely malnourished due to absorbing Donald's bad luck. Thus, Donald is released as Liu Hai and the casino fade into oblivion. The kids congratulate Donald, and the group heads back to Launchpad. Gladstone has an epiphany about his luck and almost decides to turn himself around; at that moment, a woman offers a large golden boat coasts to him for twenty dollars, so Gladstone resumes his luck-based lifestyle.
At a temple, the Duck family find the Golden Cricket, although it turns out to be an ordinary cricket. The family gets bored and tired, while a dissatisfied Scrooge agrees they can leave.