Gyro, Fenton and Huey take a malfunctioning B.O.Y.D. back to the lab where he was created in Japan, but as Huey bonds with the robot boy, a secret from Gyro's past threatens to destroy the city and Gizmoduck.
After not speaking to each other for ten years, Donald Duck reunites with his estranged uncle Scrooge McDuck when he asks him to babysit his three triplet nephews Huey, Dewey, and Louie for the day. The boys rekindle Scrooge's sense of adventure, and he invites Donald and the boys to live at McDuck Manor with him, along with his housekeeper Mrs. Beakley and her granddaughter Webby Vanderquack. Together, along with Scrooge's chauffeur and pilot Launchpad McQuack, the Ducks go on many new treasure-hunting expeditions and globe-trotting adventures while contending with villains like Flintheart Glomgold, the Beagle Boys, and Mark Beaks.